In order to queue events to video device, drivers should call:
:c:func:`v4l2_event_queue <v4l2_event_queue>`
- (:c:type:`vdev <video_device>`, :ref:`ev <v4l2-event>`)
+ (:c:type:`vdev <video_device>`, :c:type:`ev <v4l2_event>`)
The driver's only responsibility is to fill in the type and the data fields.
The other fields will be filled in by V4L2.
Subscribing to an event is via:
:c:func:`v4l2_event_subscribe <v4l2_event_subscribe>`
- (:c:type:`fh <v4l2_fh>`, :ref:`sub <v4l2-event-subscription>` ,
+ (:c:type:`fh <v4l2_fh>`, :c:type:`sub <v4l2_event_subscription>` ,
elems, :c:type:`ops <v4l2_subscribed_event_ops>`)
Unsubscribing to an event is via:
:c:func:`v4l2_event_unsubscribe <v4l2_event_unsubscribe>`
- (:c:type:`fh <v4l2_fh>`, :ref:`sub <v4l2-event-subscription>`)
+ (:c:type:`fh <v4l2_fh>`, :c:type:`sub <v4l2_event_subscription>`)
This function is used to implement :c:type:`video_device`->
:c:type:`ioctl_ops <v4l2_ioctl_ops>`-> ``vidioc_unsubscribe_event``.
All cec devices must support :ref:`ioctl CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`. To query
device information, applications call the ioctl with a pointer to a
-struct :ref:`cec_caps <cec-caps>`. The driver fills the structure and
+struct :c:type:`cec_caps`. The driver fills the structure and
returns the information to the application. The ioctl never fails.
.. tabularcolumns:: |p{1.2cm}|p{2.5cm}|p{13.8cm}|
-.. _cec-caps:
+.. c:type:: cec_caps
.. flat-table:: struct cec_caps
:header-rows: 0
.. tabularcolumns:: |p{1.0cm}|p{7.5cm}|p{8.0cm}|
-.. _cec-log-addrs:
+.. c:type:: cec_log_addrs
.. cssclass:: longtable
.. tabularcolumns:: |p{1.0cm}|p{4.2cm}|p{2.5cm}|p{8.8cm}|
-.. _cec-event:
+.. c:type:: cec_event
.. flat-table:: struct cec_event
:header-rows: 0
.. tabularcolumns:: |p{1.0cm}|p{3.5cm}|p{13.0cm}|
-.. _cec-msg:
+.. c:type:: cec_msg
.. cssclass:: longtable
} audio_channel_select_t;
-.. _audio-status:
+.. c:type:: audio_status
struct audio_status
===================
} audio_status_t;
-.. _audio-mixer:
+.. c:type:: audio_mixer
struct audio_mixer
==================
#define AUDIO_CAP_AC3 256
-.. _audio-karaoke:
+.. c:type:: audio_karaoke
struct audio_karaoke
====================
*************
-.. _ca-slot-info:
+.. c:type:: ca_slot_info
ca_slot_info_t
==============
} ca_slot_info_t;
-.. _ca-descr-info:
+.. c:type:: ca_descr_info
ca_descr_info_t
===============
} ca_descr_info_t;
-.. _ca-caps:
+.. c:type:: ca_caps
ca_caps_t
=========
} ca_cap_t;
-.. _ca-msg:
+.. c:type:: ca_msg
ca_msg_t
========
} ca_msg_t;
-.. _ca-descr:
+.. c:type:: ca_descr
ca_descr_t
==========
} ca_descr_t;
-.. _ca-pid:
+.. c:type:: ca_pid
ca-pid
======
} dmx_pes_type_t;
-.. _dmx-filter:
+.. c:type:: dmx_filter
struct dmx_filter
=================
} dmx_filter_t;
-.. _dmx-sct-filter-params:
+.. c:type:: dmx_sct_filter_params
struct dmx_sct_filter_params
============================
};
-.. _dmx-pes-filter-params:
+.. c:type:: dmx_pes_filter_params
struct dmx_pes_filter_params
============================
};
-.. _dmx-stc:
+.. c:type:: dmx_stc
struct dmx_stc
==============
};
-.. _dmx-caps:
+.. c:type:: dmx_caps
struct dmx_caps
===============
.. -*- coding: utf-8; mode: rst -*-
-.. _dtv-fe-stats:
+.. c:type:: dtv_fe_stats
*******************
struct dtv_fe_stats
.. -*- coding: utf-8; mode: rst -*-
-.. _dtv-properties:
+.. c:type:: dtv_properties
*********************
struct dtv_properties
.. -*- coding: utf-8; mode: rst -*-
-.. _dtv-property:
+.. c:type:: dtv_property
*******************
struct dtv_property
.. -*- coding: utf-8; mode: rst -*-
-.. _dtv-stats:
+.. c:type:: dtv_stats
****************
struct dtv_stats
.. -*- coding: utf-8; mode: rst -*-
-.. _dvb-frontend-event:
+.. c:type:: dvb_frontend_event
***************
frontend events
.. -*- coding: utf-8; mode: rst -*-
-.. _dvb-frontend-parameters:
+.. c:type:: dvb_frontend_parameters
*******************
frontend parameters
given in Hz.
-.. _dvb-qpsk-parameters:
+.. c:type:: dvb_qpsk_parameters
QPSK parameters
===============
};
-.. _dvb-qam-parameters:
+.. c:type:: dvb_qam_parameters
QAM parameters
==============
};
-.. _dvb-vsb-parameters:
+.. c:type:: dvb_vsb_parameters
VSB parameters
==============
};
-.. _dvb-ofdm-parameters:
+.. c:type:: dvb_ofdm_parameters
OFDM parameters
===============
.. note::
On Linux DVB API version 3, setting a frontend were done via
- :ref:`struct dvb_frontend_parameters <dvb-frontend-parameters>`.
+ :c:type:`struct dvb_frontend_parameters <dvb_frontend_parameters>`.
This got replaced on version 5 (also called "S2API", as this API were
added originally_enabled to provide support for DVB-S2), because the
old API has a very limited support to new standards and new hardware.
``argp``
pointer to struct
- :ref:`dvb_diseqc_slave_reply <dvb-diseqc-slave-reply>`
+ :c:type:`dvb_diseqc_slave_reply`
Description
Receives reply from a DiSEqC 2.0 command.
-.. _dvb-diseqc-slave-reply:
+.. c:type:: dvb_diseqc_slave_reply
struct dvb_diseqc_slave_reply
-----------------------------
``argp``
pointer to struct
- :ref:`dvb_diseqc_master_cmd <dvb-diseqc-master-cmd>`
+ :c:type:`dvb_diseqc_master_cmd`
Description
Sends a DiSEqC command to the antenna subsystem.
-.. _dvb-diseqc-master-cmd:
+.. c:type:: dvb_diseqc_master_cmd
struct dvb_diseqc_master_cmd
============================
``argp``
pointer to struct struct
- :ref:`dvb_frontend_info <dvb-frontend-info>`
+ :c:type:`dvb_frontend_info`
Description
When the driver is not compatible with this specification the ioctl
returns an error.
-.. _dvb-frontend-info:
+.. c:type:: dvb_frontend_info
struct dvb_frontend_info
========================
File descriptor returned by :ref:`open() <frontend_f_open>`.
``argp``
- pointer to struct :ref:`dtv_properties <dtv-properties>`
+ pointer to struct :c:type:`dtv_properties`
Description
ioctl's, using the :ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>`
parameter.
-In the old days, struct :ref:`dvb_frontend_info <dvb-frontend-info>`
+In the old days, struct :c:type:`dvb_frontend_info`
used to contain ``fe_type_t`` field to indicate the delivery systems,
filled with either FE_QPSK, FE_QAM, FE_OFDM or FE_ATSC. While this
is still filled to keep backward compatibility, the usage of this field
:ref:`DTV_ENUM_DELSYS <DTV-ENUM-DELSYS>` instead.
On devices that support multiple delivery systems, struct
-:ref:`dvb_frontend_info <dvb-frontend-info>`::``fe_type_t`` is
+:c:type:`dvb_frontend_info`::``fe_type_t`` is
filled with the currently standard, as selected by the last call to
:ref:`FE_SET_PROPERTY <FE_GET_PROPERTY>` using the
:ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>` property.
plus one metric per each carrier group (called "layer" on ISDB).
So, in order to be consistent with other delivery systems, the first
-value at :ref:`dtv_property.stat.dtv_stats <dtv-stats>` array refers
+value at :c:type:`dtv_property.stat.dtv_stats <dtv_stats>` array refers
to the global metric. The other elements of the array represent each
layer, starting from layer A(index 1), layer B (index 2) and so on.
File descriptor returned by :ref:`open() <frontend_f_open>`.
``net_if``
- pointer to struct :ref:`dvb_net_if <dvb-net-if>`
+ pointer to struct :c:type:`dvb_net_if`
Description
the system call successfully returns, a new virtual network interface is
created.
-The struct :ref:`dvb_net_if <dvb-net-if>`::ifnum field will be
+The struct :c:type:`dvb_net_if`::ifnum field will be
filled with the number of the created interface.
struct dvb_net_if description
=============================
-.. _dvb-net-if:
+.. c:type:: dvb_net_if
.. flat-table:: struct dvb_net_if
:header-rows: 1
File descriptor returned by :ref:`open() <frontend_f_open>`.
``net_if``
- pointer to struct :ref:`dvb_net_if <dvb-net-if>`
+ pointer to struct :c:type:`dvb_net_if`
Description
===========
The NET_GET_IF ioctl uses the interface number given by the struct
-:ref:`dvb_net_if <dvb-net-if>`::ifnum field and fills the content of
-struct :ref:`dvb_net_if <dvb-net-if>` with the packet ID and
+:c:type:`dvb_net_if`::ifnum field and fills the content of
+struct :c:type:`dvb_net_if` with the packet ID and
encapsulation type used on such interface. If the interface was not
created yet with :ref:`NET_ADD_IF <net>`, it will return -1 and fill
the ``errno`` with ``EINVAL`` error code.
} video_play_state_t;
-.. _video-command:
+.. c:type:: video_command
struct video_command
====================
} video_size_t;
-.. _video-event:
+.. c:type:: video_event
struct video_event
==================
};
-.. _video-status:
+.. c:type:: video_status
struct video_status
===================
device.
-.. _video-still-picture:
+.. c:type:: video_still_picture
struct video_still_picture
==========================
} video_system_t;
-.. _video-highlight:
+.. c:type:: video_highlight
struct video_highlight
======================
} video_highlight_t;
-.. _video-spu:
+.. c:type:: video_spu
struct video_spu
================
} video_spu_t;
-.. _video-spu-palette:
+.. c:type:: video_spu_palette
struct video_spu_palette
========================
} video_spu_palette_t;
-.. _video-navi-pack:
+.. c:type:: video_navi_pack
struct video_navi_pack
======================
All media devices must support the ``MEDIA_IOC_DEVICE_INFO`` ioctl. To
query device information, applications call the ioctl with a pointer to
-a struct :ref:`media_device_info <media-device-info>`. The driver
+a struct :c:type:`media_device_info`. The driver
fills the structure and returns the information to the application. The
ioctl never fails.
-.. _media-device-info:
+.. c:type:: media_device_info
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
===========
To query the attributes of an entity, applications set the id field of a
-struct :ref:`media_entity_desc <media-entity-desc>` structure and
+struct :c:type:`media_entity_desc` structure and
call the MEDIA_IOC_ENUM_ENTITIES ioctl with a pointer to this
structure. The driver fills the rest of the structure or returns an
EINVAL error code when the id is invalid.
id's until they get an error.
-.. _media-entity-desc:
+.. c:type:: media_entity_desc
.. tabularcolumns:: |p{1.5cm}|p{1.5cm}|p{1.5cm}|p{1.5cm}|p{11.5cm}|
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`media_entity_desc <media-entity-desc>` ``id``
+ The struct :c:type:`media_entity_desc` ``id``
references a non-existing entity.
===========
To enumerate pads and/or links for a given entity, applications set the
-entity field of a struct :ref:`media_links_enum <media-links-enum>`
+entity field of a struct :c:type:`media_links_enum`
structure and initialize the struct
-:ref:`media_pad_desc <media-pad-desc>` and struct
-:ref:`media_link_desc <media-link-desc>` structure arrays pointed by
+:c:type:`media_pad_desc` and struct
+:c:type:`media_link_desc` structure arrays pointed by
the ``pads`` and ``links`` fields. They then call the
MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this structure.
returned during the enumeration process.
-.. _media-links-enum:
+.. c:type:: media_links_enum
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 2
- - struct :ref:`media_pad_desc <media-pad-desc>`
+ - struct :c:type:`media_pad_desc`
- \*\ ``pads``
- .. row 3
- - struct :ref:`media_link_desc <media-link-desc>`
+ - struct :c:type:`media_link_desc`
- \*\ ``links``
-.. _media-pad-desc:
+.. c:type:: media_pad_desc
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _media-link-desc:
+.. c:type:: media_link_desc
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 1
- - struct :ref:`media_pad_desc <media-pad-desc>`
+ - struct :c:type:`media_pad_desc`
- ``source``
- .. row 2
- - struct :ref:`media_pad_desc <media-pad-desc>`
+ - struct :c:type:`media_pad_desc`
- ``sink``
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`media_links_enum <media-links-enum>` ``id``
+ The struct :c:type:`media_links_enum` ``id``
references a non-existing entity.
The typical usage of this ioctl is to call it twice. On the first call,
the structure defined at struct
-:ref:`media_v2_topology <media-v2-topology>` should be zeroed. At
+:c:type:`media_v2_topology` should be zeroed. At
return, if no errors happen, this ioctl will return the
``topology_version`` and the total number of entities, interfaces, pads
and links.
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
-.. _media-v2-topology:
+.. c:type:: media_v2_topology
.. flat-table:: struct media_v2_topology
:header-rows: 0
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
-.. _media-v2-entity:
+.. c:type:: media_v2_entity
.. flat-table:: struct media_v2_entity
:header-rows: 0
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
-.. _media-v2-interface:
+.. c:type:: media_v2_interface
.. flat-table:: struct media_v2_interface
:header-rows: 0
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
-.. _media-v2-intf-devnode:
+.. c:type:: media_v2_intf_devnode
.. flat-table:: struct media_v2_interface
:header-rows: 0
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
-.. _media-v2-pad:
+.. c:type:: media_v2_pad
.. flat-table:: struct media_v2_pad
:header-rows: 0
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
-.. _media-v2-link:
+.. c:type:: media_v2_link
.. flat-table:: struct media_v2_pad
:header-rows: 0
===========
To change link properties applications fill a struct
-:ref:`media_link_desc <media-link-desc>` with link identification
+:c:type:`media_link_desc` with link identification
information (source and sink pad) and the new requested link flags. They
then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to that
structure.
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`media_link_desc <media-link-desc>` references a
+ The struct :c:type:`media_link_desc` references a
non-existing link, or the link is immutable and an attempt to modify
its configuration was made.
and two audio inputs exist, there may be up to four valid combinations.
The relation of video and audio connectors is defined in the
``audioset`` field of the respective struct
-:ref:`v4l2_input <v4l2-input>` or struct
-:ref:`v4l2_output <v4l2-output>`, where each bit represents the index
+:c:type:`v4l2_input` or struct
+:c:type:`v4l2_output`, where each bit represents the index
number, starting at zero, of one audio input or output.
To learn about the number and attributes of the available inputs and
outputs applications can enumerate them with the
:ref:`VIDIOC_ENUMAUDIO` and
:ref:`VIDIOC_ENUMAUDOUT <VIDIOC_ENUMAUDOUT>` ioctl, respectively.
-The struct :ref:`v4l2_audio <v4l2-audio>` returned by the
+The struct :c:type:`v4l2_audio` returned by the
:ref:`VIDIOC_ENUMAUDIO` ioctl also contains signal
:status information applicable when the current audio input is queried.
multiple selectable audio inputs, all audio output ioctls when the
device has multiple selectable audio outputs. When the device has any
audio inputs or outputs the driver must set the ``V4L2_CAP_AUDIO`` flag
-in the struct :ref:`v4l2_capability <v4l2-capability>` returned by
+in the struct :c:type:`v4l2_capability` returned by
the :ref:`VIDIOC_QUERYCAP` ioctl.
}
.. [#f1]
- Actually struct :ref:`v4l2_audio <v4l2-audio>` ought to have a
- ``tuner`` field like struct :ref:`v4l2_input <v4l2-input>`, not
+ Actually struct :c:type:`v4l2_audio` ought to have a
+ ``tuner`` field like struct :c:type:`v4l2_input`, not
only making the API more consistent but also permitting radio devices
with multiple tuners.
planes, while the buffer structure acts as a container for the planes.
Only pointers to buffers (planes) are exchanged, the data itself is not
copied. These pointers, together with meta-information like timestamps
-or field parity, are stored in a struct :ref:`struct v4l2_buffer <v4l2-buffer>`,
+or field parity, are stored in a struct :c:type:`struct v4l2_buffer <v4l2_buffer>`,
argument to the :ref:`VIDIOC_QUERYBUF`,
:ref:`VIDIOC_QBUF` and
:ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl. In the multi-planar API,
-some plane-specific members of struct :ref:`struct v4l2_buffer <v4l2-buffer>`,
+some plane-specific members of struct :c:type:`struct v4l2_buffer <v4l2_buffer>`,
such as pointers and sizes for each plane, are stored in struct
-:ref:`struct v4l2_plane <v4l2-plane>` instead. In that case, struct
-:ref:`struct v4l2_buffer <v4l2-buffer>` contains an array of plane structures.
+:c:type:`struct v4l2_plane <v4l2_plane>` instead. In that case, struct
+:c:type:`struct v4l2_buffer <v4l2_buffer>` contains an array of plane structures.
Dequeued video buffers come with timestamps. The driver decides at which
part of the frame and with which clock the timestamp is taken. Please
buffer.
-.. _v4l2-buffer:
+.. c:type:: v4l2_buffer
struct v4l2_buffer
==================
:ref:`VIDIOC_DQBUF <VIDIOC_QBUF>`, then it is set by the
driver. This field can range from zero to the number of buffers
allocated with the :ref:`VIDIOC_REQBUFS` ioctl
- (struct :ref:`v4l2_requestbuffers <v4l2-requestbuffers>`
+ (struct :c:type:`v4l2_requestbuffers`
``count``), plus any buffers allocated with
:ref:`VIDIOC_CREATE_BUFS` minus one.
-
- Type of the buffer, same as struct
- :ref:`v4l2_format <v4l2-format>` ``type`` or struct
- :ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``type``, set
+ :c:type:`v4l2_format` ``type`` or struct
+ :c:type:`v4l2_requestbuffers` ``type``, set
by the application. See :ref:`v4l2-buf-type`
- .. row 3
- .. row 7
- - struct :ref:`v4l2_timecode <v4l2-timecode>`
+ - struct :c:type:`v4l2_timecode`
- ``timecode``
- ``*planes``
- When using the multi-planar API, contains a userspace pointer to
- an array of struct :ref:`v4l2_plane <v4l2-plane>`. The size of
+ an array of struct :c:type:`v4l2_plane`. The size of
the array should be put in the ``length`` field of this
- :ref:`struct v4l2_buffer <v4l2-buffer>` structure.
+ :c:type:`struct v4l2_buffer <v4l2_buffer>` structure.
- .. row 15
-.. _v4l2-plane:
+.. c:type:: v4l2_plane
struct v4l2_plane
=================
- ``mem_offset``
- When the memory type in the containing struct
- :ref:`v4l2_buffer <v4l2-buffer>` is ``V4L2_MEMORY_MMAP``, this
+ :c:type:`v4l2_buffer` is ``V4L2_MEMORY_MMAP``, this
is the value that should be passed to :ref:`mmap() <func-mmap>`,
similar to the ``offset`` field in struct
- :ref:`v4l2_buffer <v4l2-buffer>`.
+ :c:type:`v4l2_buffer`.
- .. row 5
- ``userptr``
- When the memory type in the containing struct
- :ref:`v4l2_buffer <v4l2-buffer>` is ``V4L2_MEMORY_USERPTR``,
+ :c:type:`v4l2_buffer` is ``V4L2_MEMORY_USERPTR``,
this is a userspace pointer to the memory allocated for this plane
by an application.
- ``fd``
- When the memory type in the containing struct
- :ref:`v4l2_buffer <v4l2-buffer>` is ``V4L2_MEMORY_DMABUF``,
+ :c:type:`v4l2_buffer` is ``V4L2_MEMORY_DMABUF``,
this is a file descriptor associated with a DMABUF buffer, similar
- to the ``fd`` field in struct :ref:`v4l2_buffer <v4l2-buffer>`.
+ to the ``fd`` field in struct :c:type:`v4l2_buffer`.
- .. row 7
Timecodes
=========
-The :ref:`struct v4l2_timecode <v4l2-timecode>` structure is designed to hold a
+The :c:type:`struct v4l2_timecode <v4l2_timecode>` structure is designed to hold a
:ref:`smpte12m` or similar timecode. (struct
:c:type:`struct timeval` timestamps are stored in struct
-:ref:`v4l2_buffer <v4l2-buffer>` field ``timestamp``.)
+:c:type:`v4l2_buffer` field ``timestamp``.)
-.. _v4l2-timecode:
+.. c:type:: v4l2_timecode
struct v4l2_timecode
--------------------
For capture devices the coordinates of the top left corner, width and
height of the area which can be sampled is given by the ``bounds``
-substructure of the struct :ref:`v4l2_cropcap <v4l2-cropcap>` returned
+substructure of the struct :c:type:`v4l2_cropcap` returned
by the :ref:`VIDIOC_CROPCAP <VIDIOC_CROPCAP>` ioctl. To support a wide
range of hardware this specification does not define an origin or units.
However by convention drivers should horizontally count unscaled samples
The top left corner, width and height of the source rectangle, that is
the area actually sampled, is given by struct
-:ref:`v4l2_crop <v4l2-crop>` using the same coordinate system as
-struct :ref:`v4l2_cropcap <v4l2-cropcap>`. Applications can use the
+:c:type:`v4l2_crop` using the same coordinate system as
+struct :c:type:`v4l2_cropcap`. Applications can use the
:ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>`
ioctls to get and set this rectangle. It must lie completely within the
capture boundaries and the driver may further adjust the requested size
Each capture device has a default source rectangle, given by the
``defrect`` substructure of struct
-:ref:`v4l2_cropcap <v4l2-cropcap>`. The center of this rectangle
+:c:type:`v4l2_cropcap`. The center of this rectangle
shall align with the center of the active picture area of the video
signal, and cover what the driver writer considers the complete picture.
Drivers shall reset the source rectangle to the default when the driver
limitations. It may only scale up or down, support only discrete scaling
factors, or have different scaling abilities in horizontal and vertical
direction. Also it may not support scaling at all. At the same time the
-struct :ref:`v4l2_crop <v4l2-crop>` rectangle may have to be aligned,
+struct :c:type:`v4l2_crop` rectangle may have to be aligned,
and both the source and target rectangles may have arbitrary upper and
lower size limits. In particular the maximum ``width`` and ``height`` in
-struct :ref:`v4l2_crop <v4l2-crop>` may be smaller than the struct
-:ref:`v4l2_cropcap <v4l2-cropcap>`. ``bounds`` area. Therefore, as
+struct :c:type:`v4l2_crop` may be smaller than the struct
+:c:type:`v4l2_cropcap`. ``bounds`` area. Therefore, as
usual, drivers are expected to adjust the requested parameters and
return the actual values selected.
Devices supporting the video capture interface set the
``V4L2_CAP_VIDEO_CAPTURE`` or ``V4L2_CAP_VIDEO_CAPTURE_MPLANE`` flag in
the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. As secondary device
functions they may also support the :ref:`video overlay <overlay>`
(``V4L2_CAP_VIDEO_OVERLAY``) and the :ref:`raw VBI capture <raw-vbi>`
defaults. An example is given in :ref:`crop`.
To query the current image format applications set the ``type`` field of
-a struct :ref:`v4l2_format <v4l2-format>` to
+a struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VIDEO_CAPTURE`` or
``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and call the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl with a pointer to this
structure. Drivers fill the struct
-:ref:`v4l2_pix_format <v4l2-pix-format>` ``pix`` or the struct
-:ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` ``pix_mp``
+:c:type:`v4l2_pix_format` ``pix`` or the struct
+:c:type:`v4l2_pix_format_mplane` ``pix_mp``
member of the ``fmt`` union.
To request different parameters applications set the ``type`` field of a
-struct :ref:`v4l2_format <v4l2-format>` as above and initialize all
-fields of the struct :ref:`v4l2_pix_format <v4l2-pix-format>`
+struct :c:type:`v4l2_format` as above and initialize all
+fields of the struct :c:type:`v4l2_pix_format`
``vbi`` member of the ``fmt`` union, or better just modify the results
of :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, and call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`
ioctl with a pointer to this structure. Drivers may adjust the
can be used to learn about hardware limitations without disabling I/O or
possibly time consuming hardware preparations.
-The contents of struct :ref:`v4l2_pix_format <v4l2-pix-format>` and
-struct :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` are
+The contents of struct :c:type:`v4l2_pix_format` and
+struct :c:type:`v4l2_pix_format_mplane` are
discussed in :ref:`pixfmt`. See also the specification of the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` and :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctls for
details. Video capture devices must implement both the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`
Devices supporting the *Video Output Overlay* interface set the
``V4L2_CAP_VIDEO_OUTPUT_OVERLAY`` flag in the ``capabilities`` field of
-struct :ref:`v4l2_capability <v4l2-capability>` returned by the
+struct :c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl.
applications can find the corresponding framebuffer device by calling
the :ref:`VIDIOC_G_FBUF <VIDIOC_G_FBUF>` ioctl. It returns, amongst
other information, the physical address of the framebuffer in the
-``base`` field of struct :ref:`v4l2_framebuffer <v4l2-framebuffer>`.
+``base`` field of struct :c:type:`v4l2_framebuffer`.
The framebuffer device ioctl ``FBIOGET_FSCREENINFO`` returns the same
address in the ``smem_start`` field of struct
:c:type:`struct fb_fix_screeninfo`. The ``FBIOGET_FSCREENINFO``
(or none) of the clipping/blending methods defined for the
:ref:`Video Overlay <overlay>` interface.
-A struct :ref:`v4l2_window <v4l2-window>` defines the size of the
+A struct :c:type:`v4l2_window` defines the size of the
source rectangle, its position in the framebuffer and the
clipping/blending method to be used for the overlay. To get the current
parameters applications set the ``type`` field of a struct
-:ref:`v4l2_format <v4l2-format>` to
+:c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY`` and call the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl. The driver fills the
-:ref:`struct v4l2_window <v4l2-window>` substructure named ``win``. It is not
+:c:type:`struct v4l2_window <v4l2_window>` substructure named ``win``. It is not
possible to retrieve a previously programmed clipping list or bitmap.
To program the source rectangle applications set the ``type`` field of a
-struct :ref:`v4l2_format <v4l2-format>` to
+struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY``, initialize the ``win``
substructure and call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl.
The driver adjusts the parameters against hardware limits and returns
about driver capabilities without actually changing driver state. Unlike
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` this also works after the overlay has been enabled.
-A struct :ref:`v4l2_crop <v4l2-crop>` defines the size and position
+A struct :c:type:`v4l2_crop` defines the size and position
of the target rectangle. The scaling factor of the overlay is implied by
-the width and height given in struct :ref:`v4l2_window <v4l2-window>`
-and struct :ref:`v4l2_crop <v4l2-crop>`. The cropping API applies to
+the width and height given in struct :c:type:`v4l2_window`
+and struct :c:type:`v4l2_crop`. The cropping API applies to
*Video Output* and *Video Output Overlay* devices in the same way as to
*Video Capture* and *Video Overlay* devices, merely reversing the
direction of the data flow. For more information see :ref:`crop`.
Devices supporting the video output interface set the
``V4L2_CAP_VIDEO_OUTPUT`` or ``V4L2_CAP_VIDEO_OUTPUT_MPLANE`` flag in
the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. As secondary device
functions they may also support the :ref:`raw VBI output <raw-vbi>`
(``V4L2_CAP_VBI_OUTPUT``) interface. At least one of the read/write or
defaults. An example is given in :ref:`crop`.
To query the current image format applications set the ``type`` field of
-a struct :ref:`v4l2_format <v4l2-format>` to
+a struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VIDEO_OUTPUT`` or ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``
and call the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl with a pointer
to this structure. Drivers fill the struct
-:ref:`v4l2_pix_format <v4l2-pix-format>` ``pix`` or the struct
-:ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` ``pix_mp``
+:c:type:`v4l2_pix_format` ``pix`` or the struct
+:c:type:`v4l2_pix_format_mplane` ``pix_mp``
member of the ``fmt`` union.
To request different parameters applications set the ``type`` field of a
-struct :ref:`v4l2_format <v4l2-format>` as above and initialize all
-fields of the struct :ref:`v4l2_pix_format <v4l2-pix-format>`
+struct :c:type:`v4l2_format` as above and initialize all
+fields of the struct :c:type:`v4l2_pix_format`
``vbi`` member of the ``fmt`` union, or better just modify the results
of :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, and call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`
ioctl with a pointer to this structure. Drivers may adjust the
can be used to learn about hardware limitations without disabling I/O or
possibly time consuming hardware preparations.
-The contents of struct :ref:`v4l2_pix_format <v4l2-pix-format>` and
-struct :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` are
+The contents of struct :c:type:`v4l2_pix_format` and
+struct :c:type:`v4l2_pix_format_mplane` are
discussed in :ref:`pixfmt`. See also the specification of the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` and :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctls for
details. Video output devices must implement both the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`
Devices supporting the video overlay interface set the
``V4L2_CAP_VIDEO_OVERLAY`` flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. The overlay I/O
method specified below must be supported. Tuners and audio inputs are
optional.
given in :ref:`crop`.
The overlay window is described by a struct
-:ref:`v4l2_window <v4l2-window>`. It defines the size of the image,
+:c:type:`v4l2_window`. It defines the size of the image,
its position over the graphics surface and the clipping to be applied.
To get the current parameters applications set the ``type`` field of a
-struct :ref:`v4l2_format <v4l2-format>` to
+struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VIDEO_OVERLAY`` and call the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl. The driver fills the
-:ref:`struct v4l2_window <v4l2-window>` substructure named ``win``. It is not
+:c:type:`struct v4l2_window <v4l2_window>` substructure named ``win``. It is not
possible to retrieve a previously programmed clipping list or bitmap.
To program the overlay window applications set the ``type`` field of a
-struct :ref:`v4l2_format <v4l2-format>` to
+struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VIDEO_OVERLAY``, initialize the ``win`` substructure and
call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl. The driver
adjusts the parameters against hardware limits and returns the actual
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` this also works after the overlay has been enabled.
The scaling factor of the overlaid image is implied by the width and
-height given in struct :ref:`v4l2_window <v4l2-window>` and the size
+height given in struct :c:type:`v4l2_window` and the size
of the cropping rectangle. For more information see :ref:`crop`.
When simultaneous capturing and overlay is supported and the hardware
code or return accordingly modified parameters.
-.. _v4l2-window:
+.. c:type:: v4l2_window
struct v4l2_window
------------------
:ref:`VIDIOC_S_FBUF <VIDIOC_G_FBUF>` applications set this field
to the desired pixel value for the chroma key. The format is the
same as the pixel format of the framebuffer (struct
- :ref:`v4l2_framebuffer <v4l2-framebuffer>` ``fmt.pixelformat``
+ :c:type:`v4l2_framebuffer` ``fmt.pixelformat``
field), with bytes in host order. E. g. for
:ref:`V4L2_PIX_FMT_BGR24 <V4L2-PIX-FMT-BGR32>` the value should
be 0xRRGGBB on a little endian, 0xBBGGRR on a big endian host.
This field was added in Linux 2.6.23, extending the
structure. However the :ref:`VIDIOC_[G|S|TRY]_FMT <VIDIOC_G_FMT>`
- ioctls, which take a pointer to a :ref:`v4l2_format <v4l2-format>`
+ ioctls, which take a pointer to a :c:type:`v4l2_format`
parent structure with padding bytes at the end, are not affected.
-.. _v4l2-clip:
+.. c:type:: v4l2_clip
struct v4l2_clip [#f4]_
-----------------------
linked list of clipping rectangles.
-.. _v4l2-rect:
+.. c:type:: v4l2_rect
struct v4l2_rect
----------------
Devices supporting the radio interface set the ``V4L2_CAP_RADIO`` and
``V4L2_CAP_TUNER`` or ``V4L2_CAP_MODULATOR`` flag in the
``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. Other combinations of
capability flags are reserved for future extensions.
Devices supporting the raw VBI capturing or output API set the
``V4L2_CAP_VBI_CAPTURE`` or ``V4L2_CAP_VBI_OUTPUT`` flags, respectively,
in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. At least one of the
read/write, streaming or asynchronous I/O methods must be supported. VBI
devices may or may not have a tuner or modulator.
parameters and then checking if the actual parameters are suitable.
To query the current raw VBI capture parameters applications set the
-``type`` field of a struct :ref:`v4l2_format <v4l2-format>` to
+``type`` field of a struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_VBI_CAPTURE`` or ``V4L2_BUF_TYPE_VBI_OUTPUT``, and call
the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl with a pointer to this
structure. Drivers fill the struct
-:ref:`v4l2_vbi_format <v4l2-vbi-format>` ``vbi`` member of the
+:c:type:`v4l2_vbi_format` ``vbi`` member of the
``fmt`` union.
To request different parameters applications set the ``type`` field of a
-struct :ref:`v4l2_format <v4l2-format>` as above and initialize all
-fields of the struct :ref:`v4l2_vbi_format <v4l2-vbi-format>`
+struct :c:type:`v4l2_format` as above and initialize all
+fields of the struct :c:type:`v4l2_vbi_format`
``vbi`` member of the ``fmt`` union, or better just modify the results
of :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, and call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`
ioctl with a pointer to this structure. Drivers return an ``EINVAL`` error
.. tabularcolumns:: |p{2.4cm}|p{4.4cm}|p{10.7cm}|
-.. _v4l2-vbi-format:
+.. c:type:: v4l2_vbi_format
.. cssclass:: longtable
To initialize the ``start`` and ``count`` fields, applications
must first determine the current video standard selection. The
:ref:`v4l2_std_id <v4l2-std-id>` or the ``framelines`` field
- of struct :ref:`v4l2_standard <v4l2-standard>` can be evaluated
+ of struct :c:type:`v4l2_standard` can be evaluated
for this purpose.
- .. row 8
Devices supporting the RDS capturing API set the
``V4L2_CAP_RDS_CAPTURE`` flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. Any tuner that
supports RDS will set the ``V4L2_TUNER_CAP_RDS`` flag in the
-``capability`` field of struct :ref:`v4l2_tuner <v4l2-tuner>`. If the
+``capability`` field of struct :c:type:`v4l2_tuner`. If the
driver only passes RDS blocks without interpreting the data the
``V4L2_TUNER_CAP_RDS_BLOCK_IO`` flag has to be set, see
:ref:`Reading RDS data <reading-rds-data>`. For future use the flag
`https://linuxtv.org/lists.php <https://linuxtv.org/lists.php>`__.
Whether an RDS signal is present can be detected by looking at the
-``rxsubchans`` field of struct :ref:`v4l2_tuner <v4l2-tuner>`: the
+``rxsubchans`` field of struct :c:type:`v4l2_tuner`: the
``V4L2_TUNER_SUB_RDS`` will be set if RDS data was detected.
Devices supporting the RDS output API set the ``V4L2_CAP_RDS_OUTPUT``
flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. Any modulator that
supports RDS will set the ``V4L2_TUNER_CAP_RDS`` flag in the
``capability`` field of struct
-:ref:`v4l2_modulator <v4l2-modulator>`. In order to enable the RDS
+:c:type:`v4l2_modulator`. In order to enable the RDS
transmission one must set the ``V4L2_TUNER_SUB_RDS`` bit in the
``txsubchans`` field of struct
-:ref:`v4l2_modulator <v4l2-modulator>`. If the driver only passes RDS
+:c:type:`v4l2_modulator`. If the driver only passes RDS
blocks without interpreting the data the ``V4L2_TUNER_CAP_RDS_BLOCK_IO``
flag has to be set. If the tuner is capable of handling RDS entities
like program identification codes and radio text, the flag
==================
-.. _v4l2-rds-data:
+.. c:type:: v4l2_rds_data
.. tabularcolumns:: |p{2.5cm}|p{2.5cm}|p{12.5cm}|
Devices supporting the SDR receiver interface set the
``V4L2_CAP_SDR_CAPTURE`` and ``V4L2_CAP_TUNER`` flag in the
``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the
device has an Analog to Digital Converter (ADC), which is a mandatory
element for the SDR receiver.
Devices supporting the SDR transmitter interface set the
``V4L2_CAP_SDR_OUTPUT`` and ``V4L2_CAP_MODULATOR`` flag in the
``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the
device has an Digital to Analog Converter (DAC), which is a mandatory
element for the SDR transmitter.
well.
To use the :ref:`format` ioctls applications set the ``type``
-field of a struct :ref:`v4l2_format <v4l2-format>` to
+field of a struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_SDR_CAPTURE`` or ``V4L2_BUF_TYPE_SDR_OUTPUT`` and use
-the struct :ref:`v4l2_sdr_format <v4l2-sdr-format>` ``sdr`` member
+the struct :c:type:`v4l2_sdr_format` ``sdr`` member
of the ``fmt`` union as needed per the desired operation. Currently
there is two fields, ``pixelformat`` and ``buffersize``, of struct
-struct :ref:`v4l2_sdr_format <v4l2-sdr-format>` which are used.
+struct :c:type:`v4l2_sdr_format` which are used.
Content of the ``pixelformat`` is V4L2 FourCC code of the data format.
The ``buffersize`` field is maximum buffer size in bytes required for
data transfer, set by the driver in order to inform application.
-.. _v4l2-sdr-format:
+.. c:type:: v4l2_sdr_format
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
Devices supporting the sliced VBI capturing or output API set the
``V4L2_CAP_SLICED_VBI_CAPTURE`` or ``V4L2_CAP_SLICED_VBI_OUTPUT`` flag
respectively, in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl. At least one of the
read/write, streaming or asynchronous :ref:`I/O methods <io>` must be
supported. Sliced VBI devices may have a tuner or modulator.
but not both at the same time.
To determine the currently selected services applications set the
-``type`` field of struct :ref:`v4l2_format <v4l2-format>` to
+``type`` field of struct :c:type:`v4l2_format` to
``V4L2_BUF_TYPE_SLICED_VBI_CAPTURE`` or
``V4L2_BUF_TYPE_SLICED_VBI_OUTPUT``, and the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl fills the ``fmt.sliced``
member, a struct
-:ref:`v4l2_sliced_vbi_format <v4l2-sliced-vbi-format>`.
+:c:type:`v4l2_sliced_vbi_format`.
Applications can request different parameters by initializing or
modifying the ``fmt.sliced`` member and calling the
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with a pointer to the
-:ref:`struct v4l2_format <v4l2-format>` structure.
+:c:type:`struct v4l2_format <v4l2_format>` structure.
The sliced VBI API is more complicated than the raw VBI API because the
hardware must be told which VBI service to expect on each scan line. Not
:ref:`select() <func-select>` call.
-.. _v4l2-sliced-vbi-format:
+.. c:type:: v4l2_sliced_vbi_format
struct v4l2_sliced_vbi_format
-----------------------------
:ref:`VIDIOC_QBUF` and
:ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl. Drivers set this field
to the size of struct
- :ref:`v4l2_sliced_vbi_data <v4l2-sliced-vbi-data>` times the
+ :c:type:`v4l2_sliced_vbi_data` times the
number of non-zero elements in the returned ``service_lines``
array (that is the number of lines potentially carrying data).
A single :ref:`read() <func-read>` or :ref:`write() <func-write>`
call must pass all data belonging to one video frame. That is an array
-of :ref:`struct v4l2_sliced_vbi_data <v4l2-sliced-vbi-data>` structures with one or
+of :c:type:`struct v4l2_sliced_vbi_data <v4l2_sliced_vbi_data>` structures with one or
more elements and a total size not exceeding ``io_size`` bytes. Likewise
in streaming I/O mode one buffer of ``io_size`` bytes must contain data
of one video frame. The ``id`` of unused
-:ref:`struct v4l2_sliced_vbi_data <v4l2-sliced-vbi-data>` elements must be zero.
+:c:type:`struct v4l2_sliced_vbi_data <v4l2_sliced_vbi_data>` elements must be zero.
-.. _v4l2-sliced-vbi-data:
+.. c:type:: v4l2_sliced_vbi_data
struct v4l2_sliced_vbi_data
---------------------------
The payload of the MPEG-2 *Private Stream 1 PES* packets that contain
sliced VBI data is specified by struct
-:ref:`v4l2_mpeg_vbi_fmt_ivtv <v4l2-mpeg-vbi-fmt-ivtv>`. The
+:c:type:`v4l2_mpeg_vbi_fmt_ivtv`. The
payload is variable length, depending on the actual number of lines of
sliced VBI data present in a video frame. The payload may be padded at
the end with unspecified fill bytes to align the end of the payload to a
number).
-.. _v4l2-mpeg-vbi-fmt-ivtv:
+.. c:type:: v4l2_mpeg_vbi_fmt_ivtv
struct v4l2_mpeg_vbi_fmt_ivtv
-----------------------------
- .. row 3
-
- - struct :ref:`v4l2_mpeg_vbi_itv0 <v4l2-mpeg-vbi-itv0>`
+ - struct :c:type:`v4l2_mpeg_vbi_itv0`
- ``itv0``
- "itv0"
- Indicates the ``itv0`` member of the union in struct
- :ref:`v4l2_mpeg_vbi_fmt_ivtv <v4l2-mpeg-vbi-fmt-ivtv>` is
+ :c:type:`v4l2_mpeg_vbi_fmt_ivtv` is
valid.
- .. row 3
- "ITV0"
- Indicates the ``ITV0`` member of the union in struct
- :ref:`v4l2_mpeg_vbi_fmt_ivtv <v4l2-mpeg-vbi-fmt-ivtv>` is
+ :c:type:`v4l2_mpeg_vbi_fmt_ivtv` is
valid and that 36 lines of sliced VBI data are present.
-.. _v4l2-mpeg-vbi-itv0:
+.. c:type:: v4l2_mpeg_vbi_itv0
struct v4l2_mpeg_vbi_itv0
-------------------------
- .. row 2
- struct
- :ref:`v4l2_mpeg_vbi_itv0_line <v4l2-mpeg-vbi-itv0-line>`
+ :c:type:`v4l2_mpeg_vbi_itv0_line`
- ``line``\ [35]
- .. row 1
- struct
- :ref:`v4l2_mpeg_vbi_itv0_line <v4l2-mpeg-vbi-itv0-line>`
+ :c:type:`v4l2_mpeg_vbi_itv0_line`
- ``line``\ [36]
-.. _v4l2-mpeg-vbi-itv0-line:
+.. c:type:: v4l2_mpeg_vbi_itv0_line
struct v4l2_mpeg_vbi_itv0_line
------------------------------
the area of the image that will be scaled up.
Crop settings are defined by a crop rectangle and represented in a
-struct :ref:`v4l2_rect <v4l2-rect>` by the coordinates of the top
+struct :c:type:`v4l2_rect` by the coordinates of the top
left corner and the rectangle size. Both the coordinates and sizes are
expressed in pixels.
The scaling operation changes the size of the image by scaling it to new
dimensions. The scaling ratio isn't specified explicitly, but is implied
from the original and scaled image sizes. Both sizes are represented by
-struct :ref:`v4l2_rect <v4l2-rect>`.
+struct :c:type:`v4l2_rect`.
Scaling support is optional. When supported by a subdev, the crop
rectangle on the subdev's sink pad is scaled to the size configured
Devices supporting the touch interface set the ``V4L2_CAP_VIDEO_CAPTURE`` flag
and the ``V4L2_CAP_TOUCH`` flag in the ``capabilities`` field of
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl.
At least one of the read/write or streaming I/O methods must be
:ref:`VIDIOC_QUERYCAP`.
The ``name`` field in struct :c:type:`struct video_capability` became
-``card`` in struct :ref:`v4l2_capability <v4l2-capability>`, ``type``
+``card`` in struct :c:type:`v4l2_capability`, ``type``
was replaced by ``capabilities``. Note V4L2 does not distinguish between
device types like this, better think of basic video input, video output
and radio devices supporting a set of related functions like video
- ``struct video_capability`` ``type``
- - struct :ref:`v4l2_capability <v4l2-capability>`
+ - struct :c:type:`v4l2_capability`
``capabilities`` flags
- Purpose
- ``VID_TYPE_CHROMAKEY``
- ``V4L2_FBUF_CAP_CHROMAKEY`` in field ``capability`` of struct
- :ref:`v4l2_framebuffer <v4l2-framebuffer>`
+ :c:type:`v4l2_framebuffer`
- Whether chromakey overlay is supported. For more information on
overlay see :ref:`overlay`.
- ``V4L2_FBUF_CAP_LIST_CLIPPING`` and
``V4L2_FBUF_CAP_BITMAP_CLIPPING`` in field ``capability`` of
- struct :ref:`v4l2_framebuffer <v4l2-framebuffer>`
+ struct :c:type:`v4l2_framebuffer`
- Whether clipping the overlaid image is supported, see
:ref:`overlay`.
- ``VID_TYPE_FRAMERAM``
- ``V4L2_FBUF_CAP_EXTERNOVERLAY`` *not set* in field ``capability``
- of struct :ref:`v4l2_framebuffer <v4l2-framebuffer>`
+ of struct :c:type:`v4l2_framebuffer`
- Whether overlay overwrites frame buffer memory, see
:ref:`overlay`.
:ref:`VIDIOC_ENUMINPUT`,
:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` and
:ref:`VIDIOC_S_INPUT <VIDIOC_G_INPUT>` using struct
-:ref:`v4l2_input <v4l2-input>` as discussed in :ref:`video`.
+:c:type:`v4l2_input` as discussed in :ref:`video`.
The ``channel`` field counting inputs was renamed to ``index``, the
video input types were renamed as follows:
- struct :c:type:`struct video_channel` ``type``
- - struct :ref:`v4l2_input <v4l2-input>` ``type``
+ - struct :c:type:`v4l2_input` ``type``
- .. row 2
However a tuner can have more than one input, i. e. RF connectors, and a
device can have multiple tuners. The index number of the tuner
associated with the input, if any, is stored in field ``tuner`` of
-struct :ref:`v4l2_input <v4l2-input>`. Enumeration of tuners is
+struct :c:type:`v4l2_input`. Enumeration of tuners is
discussed in :ref:`tuner`.
The redundant ``VIDEO_VC_TUNER`` flag was dropped. Video inputs
V4L TV or radio device. The equivalent V4L2 ioctls are
:ref:`VIDIOC_G_TUNER <VIDIOC_G_TUNER>` and
:ref:`VIDIOC_S_TUNER <VIDIOC_G_TUNER>` using struct
-:ref:`v4l2_tuner <v4l2-tuner>`. Tuners are covered in :ref:`tuner`.
+:c:type:`v4l2_tuner`. Tuners are covered in :ref:`tuner`.
The ``tuner`` field counting tuners was renamed to ``index``. The fields
``name``, ``rangelow`` and ``rangehigh`` remained unchanged.
The ``VIDEO_TUNER_PAL``, ``VIDEO_TUNER_NTSC`` and ``VIDEO_TUNER_SECAM``
flags indicating the supported video standards were dropped. This
information is now contained in the associated struct
-:ref:`v4l2_input <v4l2-input>`. No replacement exists for the
+:c:type:`v4l2_input`. No replacement exists for the
``VIDEO_TUNER_NORM`` flag indicating whether the video standard can be
switched. The ``mode`` field to select a different video standard was
replaced by a whole new set of ioctls and structures described in
The ``VIDEO_TUNER_STEREO_ON`` flag indicating stereo reception became
``V4L2_TUNER_SUB_STEREO`` in field ``rxsubchans``. This field also
permits the detection of monaural and bilingual audio, see the
-definition of struct :ref:`v4l2_tuner <v4l2-tuner>` for details.
+definition of struct :c:type:`v4l2_tuner` for details.
Presently no replacement exists for the ``VIDEO_TUNER_RDS_ON`` and
``VIDEO_TUNER_MBS_ON`` flags.
The ``VIDEO_TUNER_LOW`` flag was renamed to ``V4L2_TUNER_CAP_LOW`` in
-the struct :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field.
+the struct :c:type:`v4l2_tuner` ``capability`` field.
The ``VIDIOCGFREQ`` and ``VIDIOCSFREQ`` ioctl to change the tuner
frequency where renamed to
:ref:`VIDIOC_G_FREQUENCY <VIDIOC_G_FREQUENCY>` and
:ref:`VIDIOC_S_FREQUENCY <VIDIOC_G_FREQUENCY>`. They take a pointer
-to a struct :ref:`v4l2_frequency <v4l2-frequency>` instead of an
+to a struct :c:type:`v4l2_frequency` instead of an
unsigned long integer.
implied by the selected image format. V4L2 does not explicitly provide
such information assuming applications recognizing the format are aware
of the image depth and others need not know. The ``palette`` field moved
-into the struct :ref:`v4l2_pix_format <v4l2-pix-format>`:
+into the struct :c:type:`v4l2_pix_format`:
- struct :c:type:`struct video_picture` ``palette``
- - struct :ref:`v4l2_pix_format <v4l2-pix-format>` ``pixfmt``
+ - struct :c:type:`v4l2_pix_format` ``pixfmt``
- .. row 2
of a V4L device. The equivalent V4L2 ioctls are
:ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` and
:ref:`VIDIOC_S_AUDIO <VIDIOC_G_AUDIO>` using struct
-:ref:`v4l2_audio <v4l2-audio>` as discussed in :ref:`audio`.
+:c:type:`v4l2_audio` as discussed in :ref:`audio`.
The ``audio`` "channel number" field counting audio inputs was renamed
to ``index``.
specification, there is no way to query the selected mode. On
``VIDIOCGAUDIO`` the driver returns the *actually received* audio
programmes in this field. In the V4L2 API this information is stored in
-the struct :ref:`v4l2_tuner <v4l2-tuner>` ``rxsubchans`` and
+the struct :c:type:`v4l2_tuner` ``rxsubchans`` and
``audmode`` fields, respectively. See :ref:`tuner` for more
information on tuners. Related to audio modes struct
-:ref:`v4l2_audio <v4l2-audio>` also reports if this is a mono or
+:c:type:`v4l2_audio` also reports if this is a mono or
stereo input, regardless if the source is a tuner.
The following fields where replaced by V4L2 controls accessible with the
:c:type:`struct video_buffer` remained unchanged, except V4L2 defines
a flag to indicate non-destructive overlays instead of a ``NULL``
pointer. All other fields moved into the struct
-:ref:`v4l2_pix_format <v4l2-pix-format>` ``fmt`` substructure of
-struct :ref:`v4l2_framebuffer <v4l2-framebuffer>`. The ``depth``
+:c:type:`v4l2_pix_format` ``fmt`` substructure of
+struct :c:type:`v4l2_framebuffer`. The ``depth``
field was replaced by ``pixelformat``. See :ref:`pixfmt-rgb` for a
list of RGB formats and their respective color depths.
uses the general-purpose data format negotiation ioctls
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` and
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`. They take a pointer to a struct
-:ref:`v4l2_format <v4l2-format>` as argument. Here the ``win`` member
+:c:type:`v4l2_format` as argument. Here the ``win`` member
of the ``fmt`` union is used, a struct
-:ref:`v4l2_window <v4l2-window>`.
+:c:type:`v4l2_window`.
The ``x``, ``y``, ``width`` and ``height`` fields of struct
:c:type:`struct video_window` moved into struct
-:ref:`v4l2_rect <v4l2-rect>` substructure ``w`` of struct
+:c:type:`v4l2_rect` substructure ``w`` of struct
:c:type:`struct v4l2_window`. The ``chromakey``, ``clips``, and
``clipcount`` fields remained unchanged. Struct
:c:type:`struct video_clip` was renamed to struct
-:ref:`v4l2_clip <v4l2-clip>`, also containing a struct
+:c:type:`v4l2_clip`, also containing a struct
:c:type:`struct v4l2_rect`, but the semantics are still the same.
The ``VIDEO_WINDOW_INTERLACE`` flag was dropped. Instead applications
must set the ``field`` field to ``V4L2_FIELD_ANY`` or
``V4L2_FIELD_INTERLACED``. The ``VIDEO_WINDOW_CHROMAKEY`` flag moved
-into struct :ref:`v4l2_framebuffer <v4l2-framebuffer>`, under the new
+into struct :c:type:`v4l2_framebuffer`, under the new
name ``V4L2_FBUF_FLAG_CHROMAKEY``.
In V4L, storing a bitmap pointer in ``clips`` and setting ``clipcount``
:c:type:`struct video_capture`. The equivalent V4L2 ioctls are
:ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and
:ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` using struct
-:ref:`v4l2_crop <v4l2-crop>`, and the related
+:c:type:`v4l2_crop`, and the related
:ref:`VIDIOC_CROPCAP` ioctl. This is a rather
complex matter, see :ref:`crop` for details.
The ``x``, ``y``, ``width`` and ``height`` fields moved into struct
-:ref:`v4l2_rect <v4l2-rect>` substructure ``c`` of struct
+:c:type:`v4l2_rect` substructure ``c`` of struct
:c:type:`struct v4l2_crop`. The ``decimation`` field was dropped. In
the V4L2 API the scaling factor is implied by the size of the cropping
rectangle and the size of the captured or overlaid image.
The ``VIDEO_CAPTURE_ODD`` and ``VIDEO_CAPTURE_EVEN`` flags to capture
only the odd or even field, respectively, were replaced by
``V4L2_FIELD_TOP`` and ``V4L2_FIELD_BOTTOM`` in the field named
-``field`` of struct :ref:`v4l2_pix_format <v4l2-pix-format>` and
-struct :ref:`v4l2_window <v4l2-window>`. These structures are used to
+``field`` of struct :c:type:`v4l2_pix_format` and
+struct :c:type:`v4l2_window`. These structures are used to
select a capture or overlay format with the
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl.
``VIDIOCSWIN`` ioctls. V4L2 uses the general-purpose data format
negotiation ioctls :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` and
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`. They take a pointer to a struct
-:ref:`v4l2_format <v4l2-format>` as argument, here the struct
-:ref:`v4l2_pix_format <v4l2-pix-format>` named ``pix`` of its
+:c:type:`v4l2_format` as argument, here the struct
+:c:type:`v4l2_pix_format` named ``pix`` of its
``fmt`` union is used.
For more information about the V4L2 read interface see :ref:`rw`.
- .. row 1
- - struct :ref:`v4l2_vbi_format <v4l2-vbi-format>`
+ - struct :c:type:`v4l2_vbi_format`
- V4L, BTTV driver
An ``offset`` field does not exist, ``sample_format`` is supposed to be
``VIDEO_PALETTE_RAW``, equivalent to ``V4L2_PIX_FMT_GREY``. The
remaining fields are probably equivalent to struct
-:ref:`v4l2_vbi_format <v4l2-vbi-format>`.
+:c:type:`v4l2_vbi_format`.
Apparently only the Zoran (ZR 36120) driver implements these ioctls. The
semantics differ from those specified for V4L2 in two ways. The
Input and output devices support the streaming I/O method when the
``V4L2_CAP_STREAMING`` flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP <VIDIOC_QUERYCAP>` ioctl is set. Whether
importing DMA buffers through DMABUF file descriptors is supported is
determined by calling the :ref:`VIDIOC_REQBUFS <VIDIOC_REQBUFS>`
application. Next, these buffers are exported to the application as file
descriptors using an API which is specific for an allocator driver. Only
such file descriptor are exchanged. The descriptors and meta-information
-are passed in struct :ref:`v4l2_buffer <v4l2-buffer>` (or in struct
-:ref:`v4l2_plane <v4l2-plane>` in the multi-planar API case). The
+are passed in struct :c:type:`v4l2_buffer` (or in struct
+:c:type:`v4l2_plane` in the multi-planar API case). The
driver must be switched into DMABUF I/O mode by calling the
:ref:`VIDIOC_REQBUFS <VIDIOC_REQBUFS>` with the desired buffer type.
both queues and unlocks all buffers as a side effect. Since there is no
notion of doing anything "now" on a multitasking system, if an
application needs to synchronize with another event it should examine
- the struct :ref:`v4l2_buffer <v4l2-buffer>` ``timestamp`` of captured or
+ the struct :c:type:`v4l2_buffer` ``timestamp`` of captured or
outputted buffers.
Drivers implementing DMABUF importing I/O must support the
several controls at once.
Each of the new ioctls expects a pointer to a struct
-:ref:`v4l2_ext_controls <v4l2-ext-controls>`. This structure
+:c:type:`v4l2_ext_controls`. This structure
contains a pointer to the control array, a count of the number of
controls in that array and a control class. Control classes are used to
group similar controls into a single class. For example, control class
whether the specified control class is supported.
The control array is a struct
-:ref:`v4l2_ext_control <v4l2-ext-control>` array. The
-:ref:`struct v4l2_ext_control <v4l2-ext-control>` structure is very similar to
-struct :ref:`v4l2_control <v4l2-control>`, except for the fact that
+:c:type:`v4l2_ext_control` array. The
+:c:type:`struct v4l2_ext_control <v4l2_ext_control>` structure is very similar to
+struct :c:type:`v4l2_control`, except for the fact that
it also allows for 64-bit values and pointers to be passed.
-Since the struct :ref:`v4l2_ext_control <v4l2-ext-control>` supports
+Since the struct :c:type:`v4l2_ext_control` supports
pointers it is now also possible to have controls with compound types
such as N-dimensional arrays and/or structures. You need to specify the
``V4L2_CTRL_FLAG_NEXT_COMPOUND`` when enumerating controls to actually
All video capture and output devices must report the current field
order. Some drivers may permit the selection of a different order, to
this end applications initialize the ``field`` field of struct
-:ref:`v4l2_pix_format <v4l2-pix-format>` before calling the
+:c:type:`v4l2_pix_format` before calling the
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl. If this is not desired it
should have the value ``V4L2_FIELD_ANY`` (0).
driver must choose one of the possible field orders during
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` or
:ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>`. struct
- :ref:`v4l2_buffer <v4l2-buffer>` ``field`` can never be
+ :c:type:`v4l2_buffer` ``field`` can never be
``V4L2_FIELD_ANY``.
- .. row 2
temporal order, i. e. the older one first. To indicate the field
parity (whether the current field is a top or bottom field) the
driver or application, depending on data direction, must set
- struct :ref:`v4l2_buffer <v4l2-buffer>` ``field`` to
+ struct :c:type:`v4l2_buffer` ``field`` to
``V4L2_FIELD_TOP`` or ``V4L2_FIELD_BOTTOM``. Any two successive
fields pair to build a frame. If fields are successive, without
any dropped fields between them (fields can drop individually),
can be determined from the struct
- :ref:`v4l2_buffer <v4l2-buffer>` ``sequence`` field. This
+ :c:type:`v4l2_buffer` ``sequence`` field. This
format cannot be selected when using the read/write I/O method
since there is no way to communicate if a field was a top or
bottom field.
current selection.
A single mechanism exists to negotiate all data formats using the
-aggregate struct :ref:`v4l2_format <v4l2-format>` and the
+aggregate struct :c:type:`v4l2_format` and the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` and
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctls. Additionally the
:ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctl can be used to examine
``length``
Length of the memory area to map. This must be the same value as
returned by the driver in the struct
- :ref:`v4l2_buffer <v4l2-buffer>` ``length`` field for the
+ :c:type:`v4l2_buffer` ``length`` field for the
single-planar API, and the same value as returned by the driver in
- the struct :ref:`v4l2_plane <v4l2-plane>` ``length`` field for
+ the struct :c:type:`v4l2_plane` ``length`` field for
the multi-planar API.
``prot``
``offset``
Offset of the buffer in device memory. This must be the same value
as returned by the driver in the struct
- :ref:`v4l2_buffer <v4l2-buffer>` ``m`` union ``offset`` field for
+ :c:type:`v4l2_buffer` ``m`` union ``offset`` field for
the single-planar API, and the same value as returned by the driver
- in the struct :ref:`v4l2_plane <v4l2-plane>` ``m`` union
+ in the struct :c:type:`v4l2_plane` ``m`` union
``mem_offset`` field for the multi-planar API.
``length``
Length of the mapped buffer. This must be the same value as given to
:ref:`mmap() <func-mmap>` and returned by the driver in the struct
- :ref:`v4l2_buffer <v4l2-buffer>` ``length`` field for the
+ :c:type:`v4l2_buffer` ``length`` field for the
single-planar API and in the struct
- :ref:`v4l2_plane <v4l2-plane>` ``length`` field for the
+ :c:type:`v4l2_plane` ``length`` field for the
multi-planar API.
Codec API was released.
1998-11-08: Many minor changes. Most symbols have been renamed. Some
-material changes to struct :ref:`v4l2_capability <v4l2-capability>`.
+material changes to struct :c:type:`v4l2_capability`.
1998-11-12: The read/write directon of some ioctls was misdefined.
common Linux driver API conventions.
1. Some typos in ``V4L2_FMT_FLAG`` symbols were fixed. struct
- :ref:`v4l2_clip <v4l2-clip>` was changed for compatibility with
+ :c:type:`v4l2_clip` was changed for compatibility with
v4l. (1999-08-30)
2. ``V4L2_TUNER_SUB_LANG1`` was added. (1999-09-05)
``VIDIOC_G_INFMT``, ``VIDIOC_S_OUTFMT``, ``VIDIOC_G_OUTFMT``,
``VIDIOC_S_VBIFMT`` and ``VIDIOC_G_VBIFMT``. The image format
structure :c:type:`struct v4l2_format` was renamed to struct
- :ref:`v4l2_pix_format <v4l2-pix-format>`, while struct
- :ref:`v4l2_format <v4l2-format>` is now the envelopping structure
+ :c:type:`v4l2_pix_format`, while struct
+ :c:type:`v4l2_format` is now the envelopping structure
for all format negotiations.
5. Similar to the changes above, the ``VIDIOC_G_PARM`` and
``VIDIOC_S_PARM`` ioctls were merged with ``VIDIOC_G_OUTPARM`` and
``VIDIOC_S_OUTPARM``. A ``type`` field in the new struct
- :ref:`v4l2_streamparm <v4l2-streamparm>` selects the respective
+ :c:type:`v4l2_streamparm` selects the respective
union member.
This change obsoletes the ``VIDIOC_G_OUTPARM`` and
categories might have a greater separation, or may even appear in
separate windows.
-7. The struct :ref:`v4l2_buffer <v4l2-buffer>` ``timestamp`` was
+7. The struct :c:type:`v4l2_buffer` ``timestamp`` was
changed to a 64 bit integer, containing the sampling or output time
of the frame in nanoseconds. Additionally timestamps will be in
absolute system time, not starting from zero at the beginning of a
return a 64-bit integer.
8. A ``sequence`` field was added to struct
- :ref:`v4l2_buffer <v4l2-buffer>`. The ``sequence`` field counts
+ :c:type:`v4l2_buffer`. The ``sequence`` field counts
captured frames, it is ignored by output devices. When a capture
driver drops a frame, the sequence number of that frame is skipped.
V4L2 Version 0.20 incremental changes
=====================================
-1999-12-23: In struct :ref:`v4l2_vbi_format <v4l2-vbi-format>` the
+1999-12-23: In struct :c:type:`v4l2_vbi_format` the
``reserved1`` field became ``offset``. Previously drivers were required
to clear the ``reserved1`` field.
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctls may fail now if the struct
:c:type:`struct v4l2_fmt` ``type`` field does not contain
``V4L2_BUF_TYPE_VBI``. In the documentation of the struct
-:ref:`v4l2_vbi_format <v4l2-vbi-format>` ``offset`` field the
+:c:type:`v4l2_vbi_format` ``offset`` field the
ambiguous phrase "rising edge" was changed to "leading edge".
until the application attempts to initiate a data exchange, see
:ref:`open`.
-3. The struct :ref:`v4l2_capability <v4l2-capability>` changed
+3. The struct :c:type:`v4l2_capability` changed
dramatically. Note that also the size of the structure changed,
which is encoded in the ioctl request code, thus older V4L2 devices
will respond with an ``EINVAL`` error code to the new
``V4L2_FLAG_MONOCHROME`` flag was removed, this information is
available as described in :ref:`format`.
-4. In struct :ref:`v4l2_input <v4l2-input>` the ``assoc_audio``
+4. In struct :c:type:`v4l2_input` the ``assoc_audio``
field and the ``capability`` field and its only flag
``V4L2_INPUT_CAP_AUDIO`` was replaced by the new ``audioset`` field.
Instead of linking one video input to one audio input this field
New fields are ``tuner`` (reversing the former link from tuners to
video inputs), ``std`` and ``status``.
- Accordingly struct :ref:`v4l2_output <v4l2-output>` lost its
+ Accordingly struct :c:type:`v4l2_output` lost its
``capability`` and ``assoc_audio`` fields. ``audioset``,
``modulator`` and ``std`` where added instead.
-5. The struct :ref:`v4l2_audio <v4l2-audio>` field ``audio`` was
+5. The struct :c:type:`v4l2_audio` field ``audio`` was
renamed to ``index``, for consistency with other structures. A new
capability flag ``V4L2_AUDCAP_STEREO`` was added to indicated if the
audio input in question supports stereo sound.
(However the same applies to AVL which is still there.)
Again for consistency the struct
- :ref:`v4l2_audioout <v4l2-audioout>` field ``audio`` was renamed
+ :c:type:`v4l2_audioout` field ``audio`` was renamed
to ``index``.
-6. The struct :ref:`v4l2_tuner <v4l2-tuner>` ``input`` field was
+6. The struct :c:type:`v4l2_tuner` ``input`` field was
replaced by an ``index`` field, permitting devices with multiple
tuners. The link between video inputs and tuners is now reversed,
inputs point to their tuner. The ``std`` substructure became a
simple set (more about this below) and moved into struct
- :ref:`v4l2_input <v4l2-input>`. A ``type`` field was added.
+ :c:type:`v4l2_input`. A ``type`` field was added.
- Accordingly in struct :ref:`v4l2_modulator <v4l2-modulator>` the
+ Accordingly in struct :c:type:`v4l2_modulator` the
``output`` was replaced by an ``index`` field.
- In struct :ref:`v4l2_frequency <v4l2-frequency>` the ``port``
+ In struct :c:type:`v4l2_frequency` the ``port``
field was replaced by a ``tuner`` field containing the respective
tuner or modulator index number. A tuner ``type`` field was added
and the ``reserved`` field became larger for future extensions
:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` now take a pointer to this
type as argument. :ref:`VIDIOC_QUERYSTD` was
added to autodetect the received standard, if the hardware has this
- capability. In struct :ref:`v4l2_standard <v4l2-standard>` an
+ capability. In struct :c:type:`v4l2_standard` an
``index`` field was added for
:ref:`VIDIOC_ENUMSTD`. A
:ref:`v4l2_std_id <v4l2-std-id>` field named ``id`` was added as
Struct :c:type:`struct v4l2_enumstd` ceased to be.
:ref:`VIDIOC_ENUMSTD` now takes a pointer to a
- struct :ref:`v4l2_standard <v4l2-standard>` directly. The
+ struct :c:type:`v4l2_standard` directly. The
information which standards are supported by a particular video
- input or output moved into struct :ref:`v4l2_input <v4l2-input>`
- and struct :ref:`v4l2_output <v4l2-output>` fields named ``std``,
+ input or output moved into struct :c:type:`v4l2_input`
+ and struct :c:type:`v4l2_output` fields named ``std``,
respectively.
8. The struct :ref:`v4l2_queryctrl <v4l2-queryctrl>` fields
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`, but without the overhead of
programming the hardware and regardless of I/O in progress.
- In struct :ref:`v4l2_format <v4l2-format>` the ``fmt`` union was
- extended to contain struct :ref:`v4l2_window <v4l2-window>`. All
+ In struct :c:type:`v4l2_format` the ``fmt`` union was
+ extended to contain struct :c:type:`v4l2_window`. All
image format negotiations are now possible with ``VIDIOC_G_FMT``,
``VIDIOC_S_FMT`` and ``VIDIOC_TRY_FMT``; ioctl. The ``VIDIOC_G_WIN``
and ``VIDIOC_S_WIN`` ioctls to prepare for a video overlay were
- ``V4L2_BUF_TYPE_PRIVATE`` (but this is deprecated)
-10. In struct :ref:`v4l2_fmtdesc <v4l2-fmtdesc>` a enum
+10. In struct :c:type:`v4l2_fmtdesc` a enum
:ref:`v4l2_buf_type <v4l2-buf-type>` field named ``type`` was
- added as in struct :ref:`v4l2_format <v4l2-format>`. The
+ added as in struct :c:type:`v4l2_format`. The
``VIDIOC_ENUM_FBUFFMT`` ioctl is no longer needed and was removed.
These calls can be replaced by
:ref:`VIDIOC_ENUM_FMT` with type
``V4L2_BUF_TYPE_VIDEO_OVERLAY``.
-11. In struct :ref:`v4l2_pix_format <v4l2-pix-format>` the ``depth``
+11. In struct :c:type:`v4l2_pix_format` the ``depth``
field was removed, assuming applications which recognize the format
by its four-character-code already know the color depth, and others
do not care about it. The same rationale lead to the removal of the
``V4L2_COLORSPACE_BT878``, ``V4L2_COLORSPACE_470_SYSTEM_M`` or
``V4L2_COLORSPACE_470_SYSTEM_BG`` replaces ``V4L2_FMT_CS_601YUV``.
-12. In struct :ref:`v4l2_requestbuffers <v4l2-requestbuffers>` the
+12. In struct :c:type:`v4l2_requestbuffers` the
``type`` field was properly defined as enum
:ref:`v4l2_buf_type <v4l2-buf-type>`. Buffer types changed as
mentioned above. A new ``memory`` field of type enum
I/O methods using buffers allocated by the driver or the
application. See :ref:`io` for details.
-13. In struct :ref:`v4l2_buffer <v4l2-buffer>` the ``type`` field was
+13. In struct :c:type:`v4l2_buffer` the ``type`` field was
properly defined as enum :ref:`v4l2_buf_type <v4l2-buf-type>`.
Buffer types changed as mentioned above. A ``field`` field of type
enum :ref:`v4l2_field <v4l2-field>` was added to indicate if a
indeed allocated in device memory rather than DMA-able system
memory. It was barely useful and so was removed.
-14. In struct :ref:`v4l2_framebuffer <v4l2-framebuffer>` the
+14. In struct :c:type:`v4l2_framebuffer` the
``base[3]`` array anticipating double- and triple-buffering in
off-screen video memory, however without defining a synchronization
mechanism, was replaced by a single pointer. The
``V4L2_FBUF_CAP_LIST_CLIPPING`` and
``V4L2_FBUF_CAP_BITMAP_CLIPPING``.
-15. In struct :ref:`v4l2_clip <v4l2-clip>` the ``x``, ``y``,
+15. In struct :c:type:`v4l2_clip` the ``x``, ``y``,
``width`` and ``height`` field moved into a ``c`` substructure of
- type struct :ref:`v4l2_rect <v4l2-rect>`. The ``x`` and ``y``
+ type struct :c:type:`v4l2_rect`. The ``x`` and ``y``
fields were renamed to ``left`` and ``top``, i. e. offsets to a
context dependent origin.
-16. In struct :ref:`v4l2_window <v4l2-window>` the ``x``, ``y``,
+16. In struct :c:type:`v4l2_window` the ``x``, ``y``,
``width`` and ``height`` field moved into a ``w`` substructure as
above. A ``field`` field of type %v4l2-field; was added to
distinguish between field and frame (interlaced) overlay.
:c:type:`struct v4l2_cropcap` and :c:type:`struct v4l2_crop`
where redefined for this purpose. See :ref:`crop` for details.
-18. In struct :ref:`v4l2_vbi_format <v4l2-vbi-format>` the
+18. In struct :c:type:`v4l2_vbi_format` the
``SAMPLE_FORMAT`` field now contains a four-character-code as used
to identify video image formats and ``V4L2_PIX_FMT_GREY`` replaces
the ``V4L2_VBI_SF_UBYTE`` define. The ``reserved`` field was
extended.
-19. In struct :ref:`v4l2_captureparm <v4l2-captureparm>` the type of
+19. In struct :c:type:`v4l2_captureparm` the type of
the ``timeperframe`` field changed from unsigned long to struct
- :ref:`v4l2_fract <v4l2-fract>`. This allows the accurate
+ :c:type:`v4l2_fract`. This allows the accurate
expression of multiples of the NTSC-M frame rate 30000 / 1001. A new
field ``readbuffers`` was added to control the driver behaviour in
read I/O mode.
Similar changes were made to struct
- :ref:`v4l2_outputparm <v4l2-outputparm>`.
+ :c:type:`v4l2_outputparm`.
20. The struct :c:type:`struct v4l2_performance` and
``VIDIOC_G_PERF`` ioctl were dropped. Except when using the
===================
1. A new field ``input`` (former ``reserved[0]``) was added to the
- struct :ref:`v4l2_buffer <v4l2-buffer>` structure. Purpose of this
+ struct :c:type:`v4l2_buffer` structure. Purpose of this
field is to alternate between video inputs (e. g. cameras) in step
with the video capturing process. This function must be enabled with
the new ``V4L2_BUF_FLAG_INPUT`` flag. The ``flags`` field is no
4. The documentation of the :ref:`VIDIOC_QBUF` and
:ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctls did not mention the
- struct :ref:`v4l2_buffer <v4l2-buffer>` ``memory`` field. It was
+ struct :c:type:`v4l2_buffer` ``memory`` field. It was
also missing from examples. Also on the ``VIDIOC_DQBUF`` page the ``EIO``
error code was not documented.
============================
1. The ``V4L2_IN_ST_COLOR_KILL`` flag in struct
- :ref:`v4l2_input <v4l2-input>` not only indicates if the color
+ :c:type:`v4l2_input` not only indicates if the color
killer is enabled, but also if it is active. (The color killer
disables color decoding when it detects no color in the video signal
to improve the image quality.)
V4L2 spec erratum 2006-02-03
============================
-1. In struct :ref:`v4l2_captureparm <v4l2-captureparm>` and struct
- :ref:`v4l2_outputparm <v4l2-outputparm>` the ``timeperframe``
+1. In struct :c:type:`v4l2_captureparm` and struct
+ :c:type:`v4l2_outputparm` the ``timeperframe``
field gives the time in seconds, not microseconds.
V4L2 spec erratum 2006-02-04
============================
-1. The ``clips`` field in struct :ref:`v4l2_window <v4l2-window>`
- must point to an array of struct :ref:`v4l2_clip <v4l2-clip>`, not
+1. The ``clips`` field in struct :c:type:`v4l2_window`
+ must point to an array of struct :c:type:`v4l2_clip`, not
a linked list, because drivers ignore the struct
:c:type:`struct v4l2_clip`. ``next`` pointer.
not mentioned along with other buffer types.
2. In :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` it was clarified that the struct
- :ref:`v4l2_audio <v4l2-audio>` ``mode`` field is a flags field.
+ :c:type:`v4l2_audio` ``mode`` field is a flags field.
3. :ref:`VIDIOC_QUERYCAP` did not mention the sliced VBI and radio
capability flags.
4. In :ref:`VIDIOC_G_FREQUENCY <VIDIOC_G_FREQUENCY>` it was clarified that applications
must initialize the tuner ``type`` field of struct
- :ref:`v4l2_frequency <v4l2-frequency>` before calling
+ :c:type:`v4l2_frequency` before calling
:ref:`VIDIOC_S_FREQUENCY <VIDIOC_G_FREQUENCY>`.
5. The ``reserved`` array in struct
- :ref:`v4l2_requestbuffers <v4l2-requestbuffers>` has 2 elements,
+ :c:type:`v4l2_requestbuffers` has 2 elements,
not 32.
6. In :ref:`output` and :ref:`raw-vbi` the device file names
V4L2 in Linux 2.6.19
====================
-1. In struct :ref:`v4l2_sliced_vbi_cap <v4l2-sliced-vbi-cap>` a
+1. In struct :c:type:`v4l2_sliced_vbi_cap` a
buffer type field was added replacing a reserved field. Note on
architectures where the size of enum types differs from int types the
size of the structure changed. The
and :ref:`VIDIOC_S_FBUF <VIDIOC_G_FBUF>` ioctls for details.
A new ``global_alpha`` field was added to
- :ref:`v4l2_window <v4l2-window>`, extending the structure. This
+ :c:type:`v4l2_window`, extending the structure. This
may *break compatibility* with applications using a struct
:c:type:`struct v4l2_window` directly. However the
:ref:`VIDIOC_G/S/TRY_FMT <VIDIOC_G_FMT>` ioctls, which take a
- pointer to a :ref:`v4l2_format <v4l2-format>` parent structure
+ pointer to a :c:type:`v4l2_format` parent structure
with padding bytes at the end, are not affected.
3. The format of the ``chromakey`` field in struct
- :ref:`v4l2_window <v4l2-window>` changed from "host order RGB32"
+ :c:type:`v4l2_window` changed from "host order RGB32"
to a pixel value in the same format as the framebuffer. This may
*break compatibility* with existing applications. Drivers supporting
the "host order RGB32" format are not known.
V4L2 in Linux 3.17
==================
-1. Extended struct :ref:`v4l2_pix_format <v4l2-pix-format>`. Added
+1. Extended struct :c:type:`v4l2_pix_format`. Added
format flags.
2. Added compound control types and
1. Rewrote Colorspace chapter, added new enum
:ref:`v4l2_ycbcr_encoding <v4l2-ycbcr-encoding>` and enum
:ref:`v4l2_quantization <v4l2-quantization>` fields to struct
- :ref:`v4l2_pix_format <v4l2-pix-format>`, struct
- :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` and
+ :c:type:`v4l2_pix_format`, struct
+ :c:type:`v4l2_pix_format_mplane` and
struct :ref:`v4l2_mbus_framefmt <v4l2-mbus-framefmt>`.
Input and output devices support this I/O method when the
``V4L2_CAP_STREAMING`` flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl is set. There are two
streaming methods, to determine if the memory mapping flavor is
supported applications must call the :ref:`VIDIOC_REQBUFS` ioctl
location of the buffers in device memory can be determined with the
:ref:`VIDIOC_QUERYBUF` ioctl. In the single-planar
API case, the ``m.offset`` and ``length`` returned in a struct
-:ref:`v4l2_buffer <v4l2-buffer>` are passed as sixth and second
+:c:type:`v4l2_buffer` are passed as sixth and second
parameter to the :ref:`mmap() <func-mmap>` function. When using the
-multi-planar API, struct :ref:`v4l2_buffer <v4l2-buffer>` contains an
-array of struct :ref:`v4l2_plane <v4l2-plane>` structures, each
+multi-planar API, struct :c:type:`v4l2_buffer` contains an
+array of struct :c:type:`v4l2_plane` structures, each
containing its own ``m.offset`` and ``length``. When using the
multi-planar API, every plane of every buffer has to be mapped
separately, so the number of calls to :ref:`mmap() <func-mmap>` should
applications can enqueue in advance, or dequeue and process. They can
also enqueue in a different order than buffers have been dequeued, and
the driver can *fill* enqueued *empty* buffers in any order. [#f2]_ The
-index number of a buffer (struct :ref:`v4l2_buffer <v4l2-buffer>`
+index number of a buffer (struct :c:type:`v4l2_buffer`
``index``) plays no role here, it only identifies the buffer.
Initially all mapped buffers are in dequeued state, inaccessible by the
removes all buffers from both queues as a side effect. Since there is
no notion of doing anything "now" on a multitasking system, if an
application needs to synchronize with another event it should examine
- the struct ::ref:`v4l2_buffer <v4l2-buffer>` ``timestamp`` of captured
+ the struct ::c:type:`v4l2_buffer` ``timestamp`` of captured
or outputted buffers.
Drivers implementing memory mapping I/O must support the
.. tabularcolumns:: |p{4.0cm}|p{2.5cm}|p{11.0cm}|
-.. _v4l2-pix-format:
+.. c:type:: v4l2_pix_format
.. cssclass:: longtable
- ``priv``
- This field indicates whether the remaining fields of the
- :ref:`struct v4l2_pix_format <v4l2-pix-format>` structure, also called the
+ :c:type:`struct v4l2_pix_format <v4l2_pix_format>` structure, also called the
extended fields, are valid. When set to
``V4L2_PIX_FMT_PRIV_MAGIC``, it indicates that the extended fields
have been correctly initialized. When set to any other value it
To use the extended fields, applications must set the ``priv``
field to ``V4L2_PIX_FMT_PRIV_MAGIC``, initialize all the extended
fields and zero the unused bytes of the
- :ref:`struct v4l2_format <v4l2-format>` ``raw_data`` field.
+ :c:type:`struct v4l2_format <v4l2_format>` ``raw_data`` field.
When the ``priv`` field isn't set to ``V4L2_PIX_FMT_PRIV_MAGIC``
drivers must act as if all the extended fields were set to zero.
Multi-planar format structures
******************************
-The :ref:`struct v4l2_plane_pix_format <v4l2-plane-pix-format>` structures define size
+The :c:type:`struct v4l2_plane_pix_format <v4l2_plane_pix_format>` structures define size
and layout for each of the planes in a multi-planar format. The
-:ref:`struct v4l2_pix_format_mplane <v4l2-pix-format-mplane>` structure contains
+:c:type:`struct v4l2_pix_format_mplane <v4l2_pix_format_mplane>` structure contains
information common to all planes (such as image width and height) and an
-array of :ref:`struct v4l2_plane_pix_format <v4l2-plane-pix-format>` structures,
+array of :c:type:`struct v4l2_plane_pix_format <v4l2_plane_pix_format>` structures,
describing all planes of that format.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-plane-pix-format:
+.. c:type:: v4l2_plane_pix_format
.. flat-table:: struct v4l2_plane_pix_format
:header-rows: 0
- ``bytesperline``
- Distance in bytes between the leftmost pixels in two adjacent
- lines. See struct :ref:`v4l2_pix_format <v4l2-pix-format>`.
+ lines. See struct :c:type:`v4l2_pix_format`.
- .. row 3
.. tabularcolumns:: |p{4.4cm}|p{5.6cm}|p{7.5cm}|
-.. _v4l2-pix-format-mplane:
+.. c:type:: v4l2_pix_format_mplane
.. flat-table:: struct v4l2_pix_format_mplane
:header-rows: 0
- ``width``
- Image width in pixels. See struct
- :ref:`v4l2_pix_format <v4l2-pix-format>`.
+ :c:type:`v4l2_pix_format`.
- .. row 2
- ``height``
- Image height in pixels. See struct
- :ref:`v4l2_pix_format <v4l2-pix-format>`.
+ :c:type:`v4l2_pix_format`.
- .. row 3
- ``field``
- - See struct :ref:`v4l2_pix_format <v4l2-pix-format>`.
+ - See struct :c:type:`v4l2_pix_format`.
- .. row 5
- ``colorspace``
- - See struct :ref:`v4l2_pix_format <v4l2-pix-format>`.
+ - See struct :c:type:`v4l2_pix_format`.
- .. row 6
- - struct :ref:`v4l2_plane_pix_format <v4l2-plane-pix-format>`
+ - struct :c:type:`v4l2_plane_pix_format`
- ``plane_fmt[VIDEO_MAX_PLANES]``
non-standard Y'CbCr encodings and the fourth is the quantization
identifier (enum :ref:`v4l2_quantization <v4l2-quantization>`) to
specify non-standard quantization methods. Most of the time only the
-colorspace field of struct :ref:`v4l2_pix_format <v4l2-pix-format>`
-or struct :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>`
+colorspace field of struct :c:type:`v4l2_pix_format`
+or struct :c:type:`v4l2_pix_format_mplane`
needs to be filled in.
.. note::
Image Formats
#############
The V4L2 API was primarily designed for devices exchanging image data
-with applications. The :ref:`struct v4l2_pix_format <v4l2-pix-format>` and
-:ref:`struct v4l2_pix_format_mplane <v4l2-pix-format-mplane>` structures define the
+with applications. The :c:type:`struct v4l2_pix_format <v4l2_pix_format>` and
+:c:type:`struct v4l2_pix_format_mplane <v4l2_pix_format_mplane>` structures define the
format and layout of an image in memory. The former is used with the
single-planar API, while the latter is used with the multi-planar
version (see :ref:`planar-apis`). Image formats are negotiated with
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>`, :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`, :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>`
New structures for describing multi-planar formats are added: struct
- :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` and
- struct :ref:`v4l2_plane_pix_format <v4l2-plane-pix-format>`.
+ :c:type:`v4l2_pix_format_mplane` and
+ struct :c:type:`v4l2_plane_pix_format`.
Drivers may define new multi-planar formats, which have distinct
FourCC codes from the existing single-planar ones.
:ref:`VIDIOC_QBUF <VIDIOC_QBUF>`, :ref:`VIDIOC_DQBUF <VIDIOC_QBUF>`, :ref:`VIDIOC_QUERYBUF <VIDIOC_QUERYBUF>`
- A new struct :ref:`v4l2_plane <v4l2-plane>` structure for
+ A new struct :c:type:`v4l2_plane` structure for
describing planes is added. Arrays of this structure are passed in
the new ``m.planes`` field of struct
- :ref:`v4l2_buffer <v4l2-buffer>`.
+ :c:type:`v4l2_buffer`.
:ref:`VIDIOC_REQBUFS <VIDIOC_REQBUFS>`
Will allocate multi-planar buffers as requested.
Input and output devices support the :ref:`read() <func-read>` and
:ref:`write() <func-write>` function, respectively, when the
``V4L2_CAP_READWRITE`` flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl is set.
Drivers may need the CPU to copy the data, but they may also support DMA
configure a capture device to fill only a part of an image by abusing
V4L2 API. Cropping a smaller image from a larger one is achieved by
setting the field ``bytesperline`` at struct
-:ref:`v4l2_pix_format <v4l2-pix-format>`.
+:c:type:`v4l2_pix_format`.
Introducing an image offsets could be done by modifying field ``m_userptr``
at struct
-:ref:`v4l2_buffer <v4l2-buffer>` before calling
+:c:type:`v4l2_buffer` before calling
:ref:`VIDIOC_QBUF`. Those operations should be avoided because they are not
portable (endianness), and do not work for macroblock and Bayer formats
and mmap buffers. The selection API deals with configuration of buffer
cropping/composing in a clear, intuitive and portable way. Next, with
the selection API the concepts of the padded target and constraints
-flags are introduced. Finally, struct :ref:`v4l2_crop <v4l2-crop>`
-and struct :ref:`v4l2_cropcap <v4l2-cropcap>` have no reserved
+flags are introduced. Finally, struct :c:type:`v4l2_crop`
+and struct :c:type:`v4l2_cropcap` have no reserved
fields. Therefore there is no way to extend their functionality. The new
-struct :ref:`v4l2_selection <v4l2-selection>` provides a lot of place
+struct :c:type:`v4l2_selection` provides a lot of place
for future extensions. Driver developers are encouraged to implement
only selection API. The former cropping API would be simulated using the
new one.
Video devices typically support one or more different video standards or
variations of standards. Each video input and output may support another
set of standards. This set is reported by the ``std`` field of struct
-:ref:`v4l2_input <v4l2-input>` and struct
-:ref:`v4l2_output <v4l2-output>` returned by the
+:c:type:`v4l2_input` and struct
+:c:type:`v4l2_output` returned by the
:ref:`VIDIOC_ENUMINPUT` and
:ref:`VIDIOC_ENUMOUTPUT` ioctls, respectively.
- that does not support the video standard formats at all.
Here the driver shall set the ``std`` field of struct
-:ref:`v4l2_input <v4l2-input>` and struct
-:ref:`v4l2_output <v4l2-output>` to zero and the :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`,
+:c:type:`v4l2_input` and struct
+:c:type:`v4l2_output` to zero and the :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`,
:ref:`VIDIOC_S_STD <VIDIOC_G_STD>`, :ref:`VIDIOC_QUERYSTD` and :ref:`VIDIOC_ENUMSTD` ioctls
shall return the ``ENOTTY`` error code or the ``EINVAL`` error code.
To get and set the streaming parameters applications call the
:ref:`VIDIOC_G_PARM <VIDIOC_G_PARM>` and
:ref:`VIDIOC_S_PARM <VIDIOC_G_PARM>` ioctl, respectively. They take
-a pointer to a struct :ref:`v4l2_streamparm <v4l2-streamparm>`, which
+a pointer to a struct :c:type:`v4l2_streamparm`, which
contains a union holding separate parameters for input and output
devices.
Video input devices can have one or more tuners demodulating a RF
signal. Each tuner is associated with one or more video inputs,
depending on the number of RF connectors on the tuner. The ``type``
-field of the respective struct :ref:`v4l2_input <v4l2-input>`
+field of the respective struct :c:type:`v4l2_input`
returned by the :ref:`VIDIOC_ENUMINPUT` ioctl is
set to ``V4L2_INPUT_TYPE_TUNER`` and its ``tuner`` field contains the
index number of the tuner.
To query and change tuner properties applications use the
:ref:`VIDIOC_G_TUNER <VIDIOC_G_TUNER>` and
:ref:`VIDIOC_S_TUNER <VIDIOC_G_TUNER>` ioctls, respectively. The
-struct :ref:`v4l2_tuner <v4l2-tuner>` returned by :ref:`VIDIOC_G_TUNER <VIDIOC_G_TUNER>`
+struct :c:type:`v4l2_tuner` returned by :ref:`VIDIOC_G_TUNER <VIDIOC_G_TUNER>`
also contains signal status information applicable when the tuner of the
current video or radio input is queried.
set or video recorder. Each modulator is associated with one or more
video outputs, depending on the number of RF connectors on the
modulator. The ``type`` field of the respective struct
-:ref:`v4l2_output <v4l2-output>` returned by the
+:c:type:`v4l2_output` returned by the
:ref:`VIDIOC_ENUMOUTPUT` ioctl is set to
``V4L2_OUTPUT_TYPE_MODULATOR`` and its ``modulator`` field contains the
index number of the modulator.
is more than one at all. The modulator is solely determined by the
current video output. Drivers must support both ioctls and set the
``V4L2_CAP_MODULATOR`` flag in the struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl when the device has
one or more modulators.
To get and set the tuner or modulator radio frequency applications use
the :ref:`VIDIOC_G_FREQUENCY <VIDIOC_G_FREQUENCY>` and
:ref:`VIDIOC_S_FREQUENCY <VIDIOC_G_FREQUENCY>` ioctl which both take
-a pointer to a struct :ref:`v4l2_frequency <v4l2-frequency>`. These
+a pointer to a struct :c:type:`v4l2_frequency`. These
ioctls are used for TV and radio devices alike. Drivers must support
both ioctls when the tuner or modulator ioctls are supported, or when
the device is a radio device.
Input and output devices support this I/O method when the
``V4L2_CAP_STREAMING`` flag in the ``capabilities`` field of struct
-:ref:`v4l2_capability <v4l2-capability>` returned by the
+:c:type:`v4l2_capability` returned by the
:ref:`VIDIOC_QUERYCAP` ioctl is set. If the
particular user pointer method (not only memory mapping) is supported
must be determined by calling the :ref:`VIDIOC_REQBUFS` ioctl
methods. Buffers (planes) are allocated by the application itself, and
can reside for example in virtual or shared memory. Only pointers to
data are exchanged, these pointers and meta-information are passed in
-struct :ref:`v4l2_buffer <v4l2-buffer>` (or in struct
-:ref:`v4l2_plane <v4l2-plane>` in the multi-planar API case). The
+struct :c:type:`v4l2_buffer` (or in struct
+:c:type:`v4l2_plane` in the multi-planar API case). The
driver must be switched into user pointer I/O mode by calling the
:ref:`VIDIOC_REQBUFS` with the desired buffer type.
No buffers (planes) are allocated beforehand, consequently they are not
both queues and unlocks all buffers as a side effect. Since there is no
notion of doing anything "now" on a multitasking system, if an
application needs to synchronize with another event it should examine
- the struct :ref:`v4l2_buffer <v4l2-buffer>` ``timestamp`` of captured or
+ the struct :c:type:`v4l2_buffer` ``timestamp`` of captured or
outputted buffers.
Drivers implementing user pointer I/O must support the
Rewrote Colorspace chapter, added new enum
:ref:`v4l2_ycbcr_encoding <v4l2-ycbcr-encoding>` and enum
:ref:`v4l2_quantization <v4l2-quantization>` fields to struct
-:ref:`v4l2_pix_format <v4l2-pix-format>`, struct
-:ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` and struct
+:c:type:`v4l2_pix_format`, struct
+:c:type:`v4l2_pix_format_mplane` and struct
:ref:`v4l2_mbus_framefmt <v4l2-mbus-framefmt>`.
:revision: 3.17 / 2014-08-04 (*lp, hv*)
-Extended struct :ref:`v4l2_pix_format <v4l2-pix-format>`. Added
+Extended struct :c:type:`v4l2_pix_format`. Added
format flags. Added compound control types and VIDIOC_QUERY_EXT_CTRL.
outputs applications can enumerate them with the
:ref:`VIDIOC_ENUMINPUT` and
:ref:`VIDIOC_ENUMOUTPUT` ioctl, respectively. The
-struct :ref:`v4l2_input <v4l2-input>` returned by the
+struct :c:type:`v4l2_input` returned by the
:ref:`VIDIOC_ENUMINPUT` ioctl also contains signal
:status information applicable when the current video input is queried.
create buffers of different sizes.
To allocate the device buffers applications must initialize the relevant
-fields of the :ref:`struct v4l2_create_buffers <v4l2-create-buffers>` structure. The
+fields of the :c:type:`struct v4l2_create_buffers <v4l2_create_buffers>` structure. The
``count`` field must be set to the number of requested buffers, the
``memory`` field specifies the requested I/O method and the ``reserved``
array must be zeroed.
The ``format`` field specifies the image format that the buffers must be
able to handle. The application has to fill in this struct
-:ref:`v4l2_format <v4l2-format>`. Usually this will be done using the
+:c:type:`v4l2_format`. Usually this will be done using the
:ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` or
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctls to ensure that the
requested format is supported by the driver. Based on the format's
than the number requested.
-.. _v4l2-create-buffers:
+.. c:type:: v4l2_create_buffers
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 4
- - struct :ref:`v4l2_format <v4l2-format>`
+ - struct :c:type:`v4l2_format`
- ``format``
overlay devices.
-.. _v4l2-cropcap:
+.. c:type:: v4l2_cropcap
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 4
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``pixelaspect``
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_cropcap <v4l2-cropcap>` ``type`` is
+ The struct :c:type:`v4l2_cropcap` ``type`` is
invalid.
ENODATA
To query the driver applications must initialize the ``match.type`` and
``match.addr`` or ``match.name`` fields of a struct
-:ref:`v4l2_dbg_chip_info <v4l2-dbg-chip-info>` and call
+:c:type:`v4l2_dbg_chip_info` and call
:ref:`VIDIOC_DBG_G_CHIP_INFO` with a pointer to this structure. On success
the driver stores information about the selected chip in the ``name``
and ``flags`` fields.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-dbg-chip-info:
+.. c:type:: v4l2_dbg_chip_info
.. flat-table:: struct v4l2_dbg_chip_info
:header-rows: 0
with the ``CONFIG_VIDEO_ADV_DEBUG`` option to enable these ioctls.
To write a register applications must initialize all fields of a struct
-:ref:`v4l2_dbg_register <v4l2-dbg-register>` except for ``size`` and
+:c:type:`v4l2_dbg_register` except for ``size`` and
call ``VIDIOC_DBG_S_REGISTER`` with a pointer to this structure. The
``match.type`` and ``match.addr`` or ``match.name`` fields select a chip
on the TV card, the ``reg`` field specifies a register number and the
.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{3.5cm}|p{7.0cm}|
-.. _v4l2-dbg-match:
+.. c:type:: v4l2_dbg_match
.. flat-table:: struct v4l2_dbg_match
:header-rows: 0
-.. _v4l2-dbg-register:
+.. c:type:: v4l2_dbg_register
.. flat-table:: struct v4l2_dbg_register
:header-rows: 0
File descriptor returned by :ref:`open() <func-open>`.
``argp``
- pointer to struct :ref:`v4l2_decoder_cmd <v4l2-decoder-cmd>`.
+ pointer to struct :c:type:`v4l2_decoder_cmd`.
Description
``VIDIOC_DECODER_CMD`` sends a command to the decoder,
``VIDIOC_TRY_DECODER_CMD`` can be used to try a command without actually
executing it. To send a command applications must initialize all fields
-of a struct :ref:`v4l2_decoder_cmd <v4l2-decoder-cmd>` and call
+of a struct :c:type:`v4l2_decoder_cmd` and call
``VIDIOC_DECODER_CMD`` or ``VIDIOC_TRY_DECODER_CMD`` with a pointer to
this structure.
.. tabularcolumns:: |p{1.1cm}|p{2.4cm}|p{1.2cm}|p{1.6cm}|p{10.6cm}|
-.. _v4l2-decoder-cmd:
+.. c:type:: v4l2_decoder_cmd
.. cssclass:: longtable
===========
Dequeue an event from a video device. No input is required for this
-ioctl. All the fields of the struct :ref:`v4l2_event <v4l2-event>`
+ioctl. All the fields of the struct :c:type:`v4l2_event`
structure are filled by the driver. The file handle will also receive
exceptions which the application may get by e.g. using the select system
call.
.. tabularcolumns:: |p{3.0cm}|p{4.3cm}|p{2.5cm}|p{7.7cm}|
-.. _v4l2-event:
+.. c:type:: v4l2_event
.. cssclass: longtable
- .. row 3
-
- - struct :ref:`v4l2_event_vsync <v4l2-event-vsync>`
+ - struct :c:type:`v4l2_event_vsync`
- ``vsync``
- .. row 4
-
- - struct :ref:`v4l2_event_ctrl <v4l2-event-ctrl>`
+ - struct :c:type:`v4l2_event_ctrl`
- ``ctrl``
- .. row 5
-
- - struct :ref:`v4l2_event_frame_sync <v4l2-event-frame-sync>`
+ - struct :c:type:`v4l2_event_frame_sync`
- ``frame_sync``
- .. row 6
-
- - struct :ref:`v4l2_event_motion_det <v4l2-event-motion-det>`
+ - struct :c:type:`v4l2_event_motion_det`
- ``motion_det``
- .. row 7
-
- - struct :ref:`v4l2_event_src_change <v4l2-event-src-change>`
+ - struct :c:type:`v4l2_event_src_change`
- ``src_change``
- 1
- This event is triggered on the vertical sync. This event has a
- struct :ref:`v4l2_event_vsync <v4l2-event-vsync>` associated
+ struct :c:type:`v4l2_event_vsync` associated
with it.
- .. row 3
which you want to receive events. This event is triggered if the
control's value changes, if a button control is pressed or if the
control's flags change. This event has a struct
- :ref:`v4l2_event_ctrl <v4l2-event-ctrl>` associated with it.
+ :c:type:`v4l2_event_ctrl` associated with it.
This struct contains much of the same information as struct
:ref:`v4l2_queryctrl <v4l2-queryctrl>` and struct
- :ref:`v4l2_control <v4l2-control>`.
+ :c:type:`v4l2_control`.
If the event is generated due to a call to
:ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` or
This event type will ensure that no information is lost when more
events are raised than there is room internally. In that case the
- struct :ref:`v4l2_event_ctrl <v4l2-event-ctrl>` of the
+ struct :c:type:`v4l2_event_ctrl` of the
second-oldest event is kept, but the ``changes`` field of the
second-oldest event is ORed with the ``changes`` field of the
oldest event.
- Triggered immediately when the reception of a frame has begun.
This event has a struct
- :ref:`v4l2_event_frame_sync <v4l2-event-frame-sync>`
+ :c:type:`v4l2_event_frame_sync`
associated with it.
If the hardware needs to be stopped in the case of a buffer
underrun it might not be able to generate this event. In such
cases the ``frame_sequence`` field in struct
- :ref:`v4l2_event_frame_sync <v4l2-event-frame-sync>` will not
+ :c:type:`v4l2_event_frame_sync` will not
be incremented. This causes two consecutive frame sequence numbers
to have n times frame interval in between them.
receive events.
This event has a struct
- :ref:`v4l2_event_src_change <v4l2-event-src-change>`
+ :c:type:`v4l2_event_src_change`
associated with it. The ``changes`` bitfield denotes what has
changed for the subscribed pad. If multiple events occurred before
application could dequeue them, then the changes will have the
- Triggered whenever the motion detection state for one or more of
the regions changes. This event has a struct
- :ref:`v4l2_event_motion_det <v4l2-event-motion-det>`
+ :c:type:`v4l2_event_motion_det`
associated with it.
- .. row 8
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-event-vsync:
+.. c:type:: v4l2_event_vsync
.. flat-table:: struct v4l2_event_vsync
:header-rows: 0
.. tabularcolumns:: |p{3.5cm}|p{3.0cm}|p{1.8cm}|p{8.5cm}|
-.. _v4l2-event-ctrl:
+.. c:type:: v4l2_event_ctrl
.. flat-table:: struct v4l2_event_ctrl
:header-rows: 0
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-event-frame-sync:
+.. c:type:: v4l2_event_frame_sync
.. flat-table:: struct v4l2_event_frame_sync
:header-rows: 0
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-event-src-change:
+.. c:type:: v4l2_event_src_change
.. flat-table:: struct v4l2_event_src_change
:header-rows: 0
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-event-motion-det:
+.. c:type:: v4l2_event_motion_det
.. flat-table:: struct v4l2_event_motion_det
:header-rows: 0
To query the capabilities of the DV receiver/transmitter applications
initialize the ``pad`` field to 0, zero the reserved array of struct
-:ref:`v4l2_dv_timings_cap <v4l2-dv-timings-cap>` and call the
+:c:type:`v4l2_dv_timings_cap` and call the
``VIDIOC_DV_TIMINGS_CAP`` ioctl on a video node and the driver will fill
in the structure.
on a subdevice node. The capabilities are specific to inputs (for DV
receivers) or outputs (for DV transmitters), applications must specify
the desired pad number in the struct
-:ref:`v4l2_dv_timings_cap <v4l2-dv-timings-cap>` ``pad`` field and
+:c:type:`v4l2_dv_timings_cap` ``pad`` field and
zero the ``reserved`` array. Attempts to query capabilities on a pad
that doesn't support them will return an ``EINVAL`` error code.
.. tabularcolumns:: |p{1.2cm}|p{3.0cm}|p{13.3cm}|
-.. _v4l2-bt-timings-cap:
+.. c:type:: v4l2_bt_timings_cap
.. flat-table:: struct v4l2_bt_timings_cap
:header-rows: 0
.. tabularcolumns:: |p{1.0cm}|p{3.5cm}|p{3.5cm}|p{9.5cm}|
-.. _v4l2-dv-timings-cap:
+.. c:type:: v4l2_dv_timings_cap
.. flat-table:: struct v4l2_dv_timings_cap
:header-rows: 0
- .. row 5
-
- - struct :ref:`v4l2_bt_timings_cap <v4l2-bt-timings-cap>`
+ - struct :c:type:`v4l2_bt_timings_cap`
- ``bt``
executing it.
To send a command applications must initialize all fields of a struct
-:ref:`v4l2_encoder_cmd <v4l2-encoder-cmd>` and call
+:c:type:`v4l2_encoder_cmd` and call
``VIDIOC_ENCODER_CMD`` or ``VIDIOC_TRY_ENCODER_CMD`` with a pointer to
this structure.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-encoder-cmd:
+.. c:type:: v4l2_encoder_cmd
.. flat-table:: struct v4l2_encoder_cmd
:header-rows: 0
To query the available timings, applications initialize the ``index``
field, set the ``pad`` field to 0, zero the reserved array of struct
-:ref:`v4l2_enum_dv_timings <v4l2-enum-dv-timings>` and call the
+:c:type:`v4l2_enum_dv_timings` and call the
``VIDIOC_ENUM_DV_TIMINGS`` ioctl on a video node with a pointer to this
structure. Drivers fill the rest of the structure or return an ``EINVAL``
error code when the index is out of bounds. To enumerate all supported
subdevice node. The DV timings are specific to inputs (for DV receivers)
or outputs (for DV transmitters), applications must specify the desired
pad number in the struct
-:ref:`v4l2_enum_dv_timings <v4l2-enum-dv-timings>` ``pad`` field.
+:c:type:`v4l2_enum_dv_timings` ``pad`` field.
Attempts to enumerate timings on a pad that doesn't support them will
return an ``EINVAL`` error code.
-.. _v4l2-enum-dv-timings:
+.. c:type:: v4l2_enum_dv_timings
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 4
- - struct :ref:`v4l2_dv_timings <v4l2-dv-timings>`
+ - struct :c:type:`v4l2_dv_timings`
- ``timings``
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_enum_dv_timings <v4l2-enum-dv-timings>`
+ The struct :c:type:`v4l2_enum_dv_timings`
``index`` is out of bounds or the ``pad`` number is invalid.
ENODATA
===========
To enumerate image formats applications initialize the ``type`` and
-``index`` field of struct :ref:`v4l2_fmtdesc <v4l2-fmtdesc>` and call
+``index`` field of struct :c:type:`v4l2_fmtdesc` and call
the :ref:`VIDIOC_ENUM_FMT` ioctl with a pointer to this structure. Drivers
fill the rest of the structure or return an ``EINVAL`` error code. All
formats are enumerable by beginning at index zero and incrementing by
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-fmtdesc:
+.. c:type:: v4l2_fmtdesc
.. flat-table:: struct v4l2_fmtdesc
:header-rows: 0
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_fmtdesc <v4l2-fmtdesc>` ``type`` is not
+ The struct :c:type:`v4l2_fmtdesc` ``type`` is not
supported or the ``index`` is out of bounds.
File descriptor returned by :ref:`open() <func-open>`.
``argp``
- Pointer to a struct :ref:`v4l2_frmivalenum <v4l2-frmivalenum>`
+ Pointer to a struct :c:type:`v4l2_frmivalenum`
structure that contains a pixel format and size and receives a frame
interval.
application should zero out all members except for the *IN* fields.
-.. _v4l2-frmival-stepwise:
+.. c:type:: v4l2_frmival_stepwise
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 1
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``min``
- .. row 2
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``max``
- .. row 3
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``step``
-.. _v4l2-frmivalenum:
+.. c:type:: v4l2_frmivalenum
.. flat-table:: struct v4l2_frmivalenum
:header-rows: 0
- .. row 7
-
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``discrete``
- .. row 8
-
- - struct :ref:`v4l2_frmival_stepwise <v4l2-frmival-stepwise>`
+ - struct :c:type:`v4l2_frmival_stepwise`
- ``stepwise``
File descriptor returned by :ref:`open() <func-open>`.
``argp``
- Pointer to a struct :ref:`v4l2_frmsizeenum <v4l2-frmsizeenum>`
+ Pointer to a struct :c:type:`v4l2_frmsizeenum`
that contains an index and pixel format and receives a frame width
and height.
application should zero out all members except for the *IN* fields.
-.. _v4l2-frmsize-discrete:
+.. c:type:: v4l2_frmsize_discrete
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-frmsize-stepwise:
+.. c:type:: v4l2_frmsize_stepwise
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-frmsizeenum:
+.. c:type:: v4l2_frmsizeenum
.. flat-table:: struct v4l2_frmsizeenum
:header-rows: 0
- .. row 5
-
- - struct :ref:`v4l2_frmsize_discrete <v4l2-frmsize-discrete>`
+ - struct :c:type:`v4l2_frmsize_discrete`
- ``discrete``
- .. row 6
-
- - struct :ref:`v4l2_frmsize_stepwise <v4l2-frmsize-stepwise>`
+ - struct :c:type:`v4l2_frmsize_stepwise`
- ``stepwise``
Enumerates the frequency bands that a tuner or modulator supports. To do
this applications initialize the ``tuner``, ``type`` and ``index``
fields, and zero out the ``reserved`` array of a struct
-:ref:`v4l2_frequency_band <v4l2-frequency-band>` and call the
+:c:type:`v4l2_frequency_band` and call the
:ref:`VIDIOC_ENUM_FREQ_BANDS` ioctl with a pointer to this structure.
This ioctl is supported if the ``V4L2_TUNER_CAP_FREQ_BANDS`` capability
.. tabularcolumns:: |p{2.9cm}|p{2.9cm}|p{5.8cm}|p{2.9cm}|p{3.0cm}|
-.. _v4l2-frequency-band:
+.. c:type:: v4l2_frequency_band
.. flat-table:: struct v4l2_frequency_band
:header-rows: 0
- ``tuner``
- The tuner or modulator index number. This is the same value as in
- the struct :ref:`v4l2_input <v4l2-input>` ``tuner`` field and
- the struct :ref:`v4l2_tuner <v4l2-tuner>` ``index`` field, or
- the struct :ref:`v4l2_output <v4l2-output>` ``modulator`` field
- and the struct :ref:`v4l2_modulator <v4l2-modulator>` ``index``
+ the struct :c:type:`v4l2_input` ``tuner`` field and
+ the struct :c:type:`v4l2_tuner` ``index`` field, or
+ the struct :c:type:`v4l2_output` ``modulator`` field
+ and the struct :c:type:`v4l2_modulator` ``index``
field.
- .. row 2
- ``type``
- The tuner type. This is the same value as in the struct
- :ref:`v4l2_tuner <v4l2-tuner>` ``type`` field. The type must be
+ :c:type:`v4l2_tuner` ``type`` field. The type must be
set to ``V4L2_TUNER_RADIO`` for ``/dev/radioX`` device nodes, and
to ``V4L2_TUNER_ANALOG_TV`` for all others. Set this field to
``V4L2_TUNER_RADIO`` for modulators (currently only radio
To query the attributes of an audio input applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
-:ref:`v4l2_audio <v4l2-audio>` and call the :ref:`VIDIOC_ENUMAUDIO`
+:c:type:`v4l2_audio` and call the :ref:`VIDIOC_ENUMAUDIO`
ioctl with a pointer to this structure. Drivers fill the rest of the
structure or return an ``EINVAL`` error code when the index is out of
bounds. To enumerate all audio inputs applications shall begin at index
zero, incrementing by one until the driver returns ``EINVAL``.
See :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` for a description of struct
-:ref:`v4l2_audio <v4l2-audio>`.
+:c:type:`v4l2_audio`.
Return Value
To query the attributes of an audio output applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
-:ref:`v4l2_audioout <v4l2-audioout>` and call the ``VIDIOC_G_AUDOUT``
+:c:type:`v4l2_audioout` and call the ``VIDIOC_G_AUDOUT``
ioctl with a pointer to this structure. Drivers fill the rest of the
structure or return an ``EINVAL`` error code when the index is out of
bounds. To enumerate all audio outputs applications shall begin at index
to a sound card are not audio outputs in this sense.
See :ref:`VIDIOC_G_AUDIOout <VIDIOC_G_AUDOUT>` for a description of struct
-:ref:`v4l2_audioout <v4l2-audioout>`.
+:c:type:`v4l2_audioout`.
Return Value
===========
To query the attributes of a video input applications initialize the
-``index`` field of struct :ref:`v4l2_input <v4l2-input>` and call the
+``index`` field of struct :c:type:`v4l2_input` and call the
:ref:`VIDIOC_ENUMINPUT` ioctl with a pointer to this structure. Drivers
fill the rest of the structure or return an ``EINVAL`` error code when the
index is out of bounds. To enumerate all inputs applications shall begin
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-input:
+.. c:type:: v4l2_input
.. flat-table:: struct v4l2_input
:header-rows: 0
- Capture devices can have zero or more tuners (RF demodulators).
When the ``type`` is set to ``V4L2_INPUT_TYPE_TUNER`` this is an
RF connector and this field identifies the tuner. It corresponds
- to struct :ref:`v4l2_tuner <v4l2-tuner>` field ``index``. For
+ to struct :c:type:`v4l2_tuner` field ``index``. For
details on tuners see :ref:`tuner`.
- .. row 6
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_input <v4l2-input>` ``index`` is out of
+ The struct :c:type:`v4l2_input` ``index`` is out of
bounds.
===========
To query the attributes of a video outputs applications initialize the
-``index`` field of struct :ref:`v4l2_output <v4l2-output>` and call
+``index`` field of struct :c:type:`v4l2_output` and call
the :ref:`VIDIOC_ENUMOUTPUT` ioctl with a pointer to this structure.
Drivers fill the rest of the structure or return an ``EINVAL`` error code
when the index is out of bounds. To enumerate all outputs applications
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-output:
+.. c:type:: v4l2_output
.. flat-table:: struct v4l2_output
:header-rows: 0
- Output devices can have zero or more RF modulators. When the
``type`` is ``V4L2_OUTPUT_TYPE_MODULATOR`` this is an RF connector
and this field identifies the modulator. It corresponds to struct
- :ref:`v4l2_modulator <v4l2-modulator>` field ``index``. For
+ :c:type:`v4l2_modulator` field ``index``. For
details on modulators see :ref:`tuner`.
- .. row 6
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_output <v4l2-output>` ``index`` is out of
+ The struct :c:type:`v4l2_output` ``index`` is out of
bounds.
To query the attributes of a video standard, especially a custom (driver
defined) one, applications initialize the ``index`` field of struct
-:ref:`v4l2_standard <v4l2-standard>` and call the :ref:`VIDIOC_ENUMSTD`
+:c:type:`v4l2_standard` and call the :ref:`VIDIOC_ENUMSTD`
ioctl with a pointer to this structure. Drivers fill the rest of the
structure or return an ``EINVAL`` error code when the index is out of
bounds. To enumerate all standards applications shall begin at index
or output. [#f1]_
-.. _v4l2-standard:
+.. c:type:: v4l2_standard
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
set as custom standards. Multiple bits can be set if the hardware
does not distinguish between these standards, however separate
indices do not indicate the opposite. The ``id`` must be unique.
- No other enumerated :ref:`struct v4l2_standard <v4l2-standard>` structure,
+ No other enumerated :c:type:`struct v4l2_standard <v4l2_standard>` structure,
for this input or output anyway, can contain the same set of bits.
- .. row 3
- .. row 4
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``frameperiod``
-.. _v4l2-fract:
+.. c:type:: v4l2_fract
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_standard <v4l2-standard>` ``index`` is out
+ The struct :c:type:`v4l2_standard` ``index`` is out
of bounds.
ENODATA
:ref:`VIDIOC_REQBUFS` ioctl.
To export a buffer, applications fill struct
-:ref:`v4l2_exportbuffer <v4l2-exportbuffer>`. The ``type`` field is
+:c:type:`v4l2_exportbuffer`. The ``type`` field is
set to the same buffer type as was previously used with struct
-:ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``type``.
+:c:type:`v4l2_requestbuffers` ``type``.
Applications must also set the ``index`` field. Valid index numbers
range from zero to the number of buffers allocated with
:ref:`VIDIOC_REQBUFS` (struct
-:ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``count``) minus
+:c:type:`v4l2_requestbuffers` ``count``) minus
one. For the multi-planar API, applications set the ``plane`` field to
the index of the plane to be exported. Valid planes range from zero to
the maximal number of valid planes for the currently active format. For
}
-.. _v4l2-exportbuffer:
+.. c:type:: v4l2_exportbuffer
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- ``type``
- Type of the buffer, same as struct
- :ref:`v4l2_format <v4l2-format>` ``type`` or struct
- :ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``type``, set
+ :c:type:`v4l2_format` ``type`` or struct
+ :c:type:`v4l2_requestbuffers` ``type``, set
by the application. See :ref:`v4l2-buf-type`
- .. row 2
===========
To query the current audio input applications zero out the ``reserved``
-array of a struct :ref:`v4l2_audio <v4l2-audio>` and call the
+array of a struct :c:type:`v4l2_audio` and call the
:ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` ioctl with a pointer to this structure. Drivers fill
the rest of the structure or return an ``EINVAL`` error code when the device
has no audio inputs, or none which combine with the current video input.
Audio inputs have one writable property, the audio mode. To select the
current audio input *and* change the audio mode, applications initialize
the ``index`` and ``mode`` fields, and the ``reserved`` array of a
-:ref:`struct v4l2_audio <v4l2-audio>` structure and call the :ref:`VIDIOC_S_AUDIO <VIDIOC_G_AUDIO>`
+:c:type:`struct v4l2_audio <v4l2_audio>` structure and call the :ref:`VIDIOC_S_AUDIO <VIDIOC_G_AUDIO>`
ioctl. Drivers may switch to a different audio mode if the request
cannot be satisfied. However, this is a write-only ioctl, it does not
return the actual new audio mode.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-audio:
+.. c:type:: v4l2_audio
.. flat-table:: struct v4l2_audio
:header-rows: 0
===========
To query the current audio output applications zero out the ``reserved``
-array of a struct :ref:`v4l2_audioout <v4l2-audioout>` and call the
+array of a struct :c:type:`v4l2_audioout` and call the
``VIDIOC_G_AUDOUT`` ioctl with a pointer to this structure. Drivers fill
the rest of the structure or return an ``EINVAL`` error code when the device
has no audio inputs, or none which combine with the current video
Audio outputs have no writable properties. Nevertheless, to select the
current audio output applications can initialize the ``index`` field and
``reserved`` array (which in the future may contain writable properties)
-of a :ref:`struct v4l2_audioout <v4l2-audioout>` structure and call the
+of a :c:type:`struct v4l2_audioout <v4l2_audioout>` structure and call the
``VIDIOC_S_AUDOUT`` ioctl. Drivers switch to the requested output or
return the ``EINVAL`` error code when the index is out of bounds. This is a
write-only ioctl, it does not return the current audio output attributes
to a sound card are not audio outputs in this sense.
-.. _v4l2-audioout:
+.. c:type:: v4l2_audioout
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
===========
To query the cropping rectangle size and position applications set the
-``type`` field of a :ref:`struct v4l2_crop <v4l2-crop>` structure to the
+``type`` field of a :c:type:`struct v4l2_crop <v4l2_crop>` structure to the
respective buffer (stream) type and call the :ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` ioctl
with a pointer to this structure. The driver fills the rest of the
structure or returns the ``EINVAL`` error code if cropping is not supported.
To change the cropping rectangle applications initialize the ``type``
-and struct :ref:`v4l2_rect <v4l2-rect>` substructure named ``c`` of a
+and struct :c:type:`v4l2_rect` substructure named ``c`` of a
v4l2_crop structure and call the :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` ioctl with a pointer
to this structure.
:ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` returns the ``EINVAL`` error code.
-.. _v4l2-crop:
+.. c:type:: v4l2_crop
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 2
- - struct :ref:`v4l2_rect <v4l2-rect>`
+ - struct :c:type:`v4l2_rect`
- ``c``
- Cropping rectangle. The same co-ordinate system as for struct
- :ref:`v4l2_cropcap <v4l2-cropcap>` ``bounds`` is used.
+ :c:type:`v4l2_cropcap` ``bounds`` is used.
Return Value
===========
To get the current value of a control applications initialize the ``id``
-field of a struct :ref:`struct v4l2_control <v4l2-control>` and call the
+field of a struct :c:type:`struct v4l2_control <v4l2_control>` and call the
:ref:`VIDIOC_G_CTRL <VIDIOC_G_CTRL>` ioctl with a pointer to this structure. To change the
value of a control applications initialize the ``id`` and ``value``
-fields of a struct :ref:`struct v4l2_control <v4l2-control>` and call the
+fields of a struct :c:type:`struct v4l2_control <v4l2_control>` and call the
:ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` ioctl.
When the ``id`` is invalid drivers return an ``EINVAL`` error code. When the
:ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` must be used.
-.. _v4l2-control:
+.. c:type:: v4l2_control
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_control <v4l2-control>` ``id`` is invalid
+ The struct :c:type:`v4l2_control` ``id`` is invalid
or the ``value`` is inappropriate for the given control (i.e. if a
menu item is selected that is not supported by the driver according
to :ref:`VIDIOC_QUERYMENU <VIDIOC_QUERYCTRL>`).
ERANGE
- The struct :ref:`v4l2_control <v4l2-control>` ``value`` is out of
+ The struct :c:type:`v4l2_control` ``value`` is out of
bounds.
EBUSY
:ref:`VIDIOC_S_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl and to get the current timings,
applications use the :ref:`VIDIOC_G_DV_TIMINGS <VIDIOC_G_DV_TIMINGS>` ioctl. The detailed timing
information is filled in using the structure struct
-:ref:`v4l2_dv_timings <v4l2-dv-timings>`. These ioctls take a
-pointer to the struct :ref:`v4l2_dv_timings <v4l2-dv-timings>`
+:c:type:`v4l2_dv_timings`. These ioctls take a
+pointer to the struct :c:type:`v4l2_dv_timings`
structure as argument. If the ioctl is not supported or the timing
values are not correct, the driver returns ``EINVAL`` error code.
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-bt-timings:
+.. c:type:: v4l2_bt_timings
.. flat-table:: struct v4l2_bt_timings
:header-rows: 0
.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{7.0cm}|p{3.5cm}|
-.. _v4l2-dv-timings:
+.. c:type:: v4l2_dv_timings
.. flat-table:: struct v4l2_dv_timings
:header-rows: 0
- .. row 3
-
- - struct :ref:`v4l2_bt_timings <v4l2-bt-timings>`
+ - struct :c:type:`v4l2_bt_timings`
- ``bt``
decoding it.
To read the data applications must call :ref:`VIDIOC_G_ENC_INDEX <VIDIOC_G_ENC_INDEX>` with a
-pointer to a struct :ref:`v4l2_enc_idx <v4l2-enc-idx>`. On success
+pointer to a struct :c:type:`v4l2_enc_idx`. On success
the driver fills the ``entry`` array, stores the number of elements
written in the ``entries`` field, and initializes the ``entries_cap``
field.
.. tabularcolumns:: |p{3.5cm}|p{5.6cm}|p{8.4cm}|
-.. _v4l2-enc-idx:
+.. c:type:: v4l2_enc_idx
.. flat-table:: struct v4l2_enc_idx
:header-rows: 0
- .. row 4
- - struct :ref:`v4l2_enc_idx_entry <v4l2-enc-idx-entry>`
+ - struct :c:type:`v4l2_enc_idx_entry`
- ``entry``\ [``V4L2_ENC_IDX_ENTRIES``]
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-enc-idx-entry:
+.. c:type:: v4l2_enc_idx_entry
.. flat-table:: struct v4l2_enc_idx_entry
:header-rows: 0
Applications must always fill in the ``count``, ``which``, ``controls``
and ``reserved`` fields of struct
-:ref:`v4l2_ext_controls <v4l2-ext-controls>`, and initialize the
-struct :ref:`v4l2_ext_control <v4l2-ext-control>` array pointed to
+:c:type:`v4l2_ext_controls`, and initialize the
+struct :c:type:`v4l2_ext_control` array pointed to
by the ``controls`` fields.
To get the current value of a set of controls applications initialize
the ``id``, ``size`` and ``reserved2`` fields of each struct
-:ref:`v4l2_ext_control <v4l2-ext-control>` and call the
+:c:type:`v4l2_ext_control` and call the
:ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` ioctl. String controls controls must also set the
``string`` field. Controls of compound types
(``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is set) must set the ``ptr`` field.
To change the value of a set of controls applications initialize the
``id``, ``size``, ``reserved2`` and ``value/value64/string/ptr`` fields
-of each struct :ref:`v4l2_ext_control <v4l2-ext-control>` and call
+of each struct :c:type:`v4l2_ext_control` and call
the :ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` ioctl. The controls will only be set if *all*
control values are valid.
To check if a set of controls have correct values applications
initialize the ``id``, ``size``, ``reserved2`` and
``value/value64/string/ptr`` fields of each struct
-:ref:`v4l2_ext_control <v4l2-ext-control>` and call the
+:c:type:`v4l2_ext_control` and call the
:ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` ioctl. It is up to the driver whether wrong
values are automatically adjusted to a valid value or if an error is
returned.
code. When the value is out of bounds drivers can choose to take the
closest valid value or return an ``ERANGE`` error code, whatever seems more
appropriate. In the first case the new value is set in struct
-:ref:`v4l2_ext_control <v4l2-ext-control>`. If the new control value
+:c:type:`v4l2_ext_control`. If the new control value
is inappropriate (e.g. the given menu index is not supported by the menu
control), then this will also result in an ``EINVAL`` error code error.
.. tabularcolumns:: |p{1.2cm}|p{3.0cm}|p{1.5cm}|p{11.8cm}|
-.. _v4l2-ext-control:
+.. c:type:: v4l2_ext_control
.. cssclass: longtable
.. tabularcolumns:: |p{4.0cm}|p{2.0cm}|p{2.0cm}|p{8.5cm}|
-.. _v4l2-ext-controls:
+.. c:type:: v4l2_ext_controls
.. cssclass:: longtable
- .. row 7
- - struct :ref:`v4l2_ext_control <v4l2-ext-control>` *
+ - struct :c:type:`v4l2_ext_control` *
- ``controls``
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_ext_control <v4l2-ext-control>` ``id`` is
- invalid, the struct :ref:`v4l2_ext_controls <v4l2-ext-controls>`
+ The struct :c:type:`v4l2_ext_control` ``id`` is
+ invalid, the struct :c:type:`v4l2_ext_controls`
``which`` is invalid, or the struct
- :ref:`v4l2_ext_control <v4l2-ext-control>` ``value`` was
+ :c:type:`v4l2_ext_control` ``value`` was
inappropriate (e.g. the given menu index is not supported by the
driver). This error code is also returned by the
:ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` and :ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` ioctls if two or
more control values are in conflict.
ERANGE
- The struct :ref:`v4l2_ext_control <v4l2-ext-control>` ``value``
+ The struct :c:type:`v4l2_ext_control` ``value``
is out of bounds.
EBUSY
always non-destructive.
To get the current parameters applications call the :ref:`VIDIOC_G_FBUF <VIDIOC_G_FBUF>`
-ioctl with a pointer to a :ref:`struct v4l2_framebuffer <v4l2-framebuffer>`
+ioctl with a pointer to a :c:type:`struct v4l2_framebuffer <v4l2_framebuffer>`
structure. The driver fills all fields of the structure or returns an
EINVAL error code when overlays are not supported.
To set the parameters for a *Video Output Overlay*, applications must
initialize the ``flags`` field of a struct
-:ref:`struct v4l2_framebuffer <v4l2-framebuffer>`. Since the framebuffer is
+:c:type:`struct v4l2_framebuffer <v4l2_framebuffer>`. Since the framebuffer is
implemented on the TV card all other parameters are determined by the
driver. When an application calls :ref:`VIDIOC_S_FBUF <VIDIOC_G_FBUF>` with a pointer to
this structure, the driver prepares for the overlay and returns the
.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{3.5cm}|p{7.0cm}|
-.. _v4l2-framebuffer:
+.. c:type:: v4l2_framebuffer
.. cssclass:: longtable
-
-
- For *non-destructive Video Overlays* this field only defines a
- format for the struct :ref:`v4l2_window <v4l2-window>`
+ format for the struct :c:type:`v4l2_window`
``chromakey`` field.
- .. row 10
- Drivers and applications shall ignore this field. If applicable,
the field order is selected with the
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl, using the ``field``
- field of struct :ref:`v4l2_window <v4l2-window>`.
+ field of struct :c:type:`v4l2_window`.
- .. row 13
- 0x0004
- Use chroma-keying. The chroma-key color is determined by the
- ``chromakey`` field of struct :ref:`v4l2_window <v4l2-window>`
+ ``chromakey`` field of struct :c:type:`v4l2_window`
and negotiated with the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`
ioctl, see :ref:`overlay` and :ref:`osd`.
images. The blend function is: output = (framebuffer pixel * alpha
+ video pixel * (255 - alpha)) / 255. The alpha value is
determined by the ``global_alpha`` field of struct
- :ref:`v4l2_window <v4l2-window>` and negotiated with the
+ :c:type:`v4l2_window` and negotiated with the
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl, see :ref:`overlay`
and :ref:`osd`.
- Use source chroma-keying. The source chroma-key color is
determined by the ``chromakey`` field of struct
- :ref:`v4l2_window <v4l2-window>` and negotiated with the
+ :c:type:`v4l2_window` and negotiated with the
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl, see :ref:`overlay`
and :ref:`osd`. Both chroma-keying are mutual exclusive to each
other, so same ``chromakey`` field of struct
- :ref:`v4l2_window <v4l2-window>` is being used.
+ :c:type:`v4l2_window` is being used.
Return Value
format) exchanged between driver and application.
To query the current parameters applications set the ``type`` field of a
-struct :ref:`struct v4l2_format <v4l2-format>` to the respective buffer (stream)
+struct :c:type:`struct v4l2_format <v4l2_format>` to the respective buffer (stream)
type. For example video capture devices use
``V4L2_BUF_TYPE_VIDEO_CAPTURE`` or
``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``. When the application calls the
:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl with a pointer to this structure the driver fills
the respective member of the ``fmt`` union. In case of video capture
devices that is either the struct
-:ref:`v4l2_pix_format <v4l2-pix-format>` ``pix`` or the struct
-:ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>` ``pix_mp``
+:c:type:`v4l2_pix_format` ``pix`` or the struct
+:c:type:`v4l2_pix_format_mplane` ``pix_mp``
member. When the requested buffer type is not supported drivers return
an ``EINVAL`` error code.
:ref:`devices`. Good practice is to query the current parameters
first, and to modify only those parameters not suitable for the
application. When the application calls the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
-a pointer to a :ref:`struct v4l2_format <v4l2-format>` structure the driver
+a pointer to a :c:type:`struct v4l2_format <v4l2_format>` structure the driver
checks and adjusts the parameters against hardware abilities. Drivers
should not return an error code unless the ``type`` field is invalid,
this is a mechanism to fathom device capabilities and to approach
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` returns for the same input or output.
-.. _v4l2-format:
+.. c:type:: v4l2_format
.. tabularcolumns:: |p{1.2cm}|p{4.3cm}|p{3.0cm}|p{9.0cm}|
- .. row 3
-
- - struct :ref:`v4l2_pix_format <v4l2-pix-format>`
+ - struct :c:type:`v4l2_pix_format`
- ``pix``
- .. row 4
-
- - struct :ref:`v4l2_pix_format_mplane <v4l2-pix-format-mplane>`
+ - struct :c:type:`v4l2_pix_format_mplane`
- ``pix_mp``
- .. row 5
-
- - struct :ref:`v4l2_window <v4l2-window>`
+ - struct :c:type:`v4l2_window`
- ``win``
- .. row 6
-
- - struct :ref:`v4l2_vbi_format <v4l2-vbi-format>`
+ - struct :c:type:`v4l2_vbi_format`
- ``vbi``
- .. row 7
-
- - struct :ref:`v4l2_sliced_vbi_format <v4l2-sliced-vbi-format>`
+ - struct :c:type:`v4l2_sliced_vbi_format`
- ``sliced``
- .. row 8
-
- - struct :ref:`v4l2_sdr_format <v4l2-sdr-format>`
+ - struct :c:type:`v4l2_sdr_format`
- ``sdr``
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_format <v4l2-format>` ``type`` field is
+ The struct :c:type:`v4l2_format` ``type`` field is
invalid or the requested buffer type not supported.
To get the current tuner or modulator radio frequency applications set
the ``tuner`` field of a struct
-:ref:`v4l2_frequency <v4l2-frequency>` to the respective tuner or
+:c:type:`v4l2_frequency` to the respective tuner or
modulator number (only input devices have tuners, only output devices
have modulators), zero out the ``reserved`` array and call the
:ref:`VIDIOC_G_FREQUENCY <VIDIOC_G_FREQUENCY>` ioctl with a pointer to this structure. The
To change the current tuner or modulator radio frequency applications
initialize the ``tuner``, ``type`` and ``frequency`` fields, and the
-``reserved`` array of a struct :ref:`v4l2_frequency <v4l2-frequency>`
+``reserved`` array of a struct :c:type:`v4l2_frequency`
and call the :ref:`VIDIOC_S_FREQUENCY <VIDIOC_G_FREQUENCY>` ioctl with a pointer to this
structure. When the requested frequency is not possible the driver
assumes the closest possible value. However :ref:`VIDIOC_S_FREQUENCY <VIDIOC_G_FREQUENCY>` is a
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-frequency:
+.. c:type:: v4l2_frequency
.. flat-table:: struct v4l2_frequency
:header-rows: 0
- ``tuner``
- The tuner or modulator index number. This is the same value as in
- the struct :ref:`v4l2_input <v4l2-input>` ``tuner`` field and
- the struct :ref:`v4l2_tuner <v4l2-tuner>` ``index`` field, or
- the struct :ref:`v4l2_output <v4l2-output>` ``modulator`` field
- and the struct :ref:`v4l2_modulator <v4l2-modulator>` ``index``
+ the struct :c:type:`v4l2_input` ``tuner`` field and
+ the struct :c:type:`v4l2_tuner` ``index`` field, or
+ the struct :c:type:`v4l2_output` ``modulator`` field
+ and the struct :c:type:`v4l2_modulator` ``index``
field.
- .. row 2
- ``type``
- The tuner type. This is the same value as in the struct
- :ref:`v4l2_tuner <v4l2-tuner>` ``type`` field. The type must be
+ :c:type:`v4l2_tuner` ``type`` field. The type must be
set to ``V4L2_TUNER_RADIO`` for ``/dev/radioX`` device nodes, and
to ``V4L2_TUNER_ANALOG_TV`` for all others. Set this field to
``V4L2_TUNER_RADIO`` for modulators (currently only radio
- ``frequency``
- Tuning frequency in units of 62.5 kHz, or if the struct
- :ref:`v4l2_tuner <v4l2-tuner>` or struct
- :ref:`v4l2_modulator <v4l2-modulator>` ``capability`` flag
+ :c:type:`v4l2_tuner` or struct
+ :c:type:`v4l2_modulator` ``capability`` flag
``V4L2_TUNER_CAP_LOW`` is set, in units of 62.5 Hz. A 1 Hz unit is
used when the ``capability`` flag ``V4L2_TUNER_CAP_1HZ`` is set.
To query the current video input applications call the
:ref:`VIDIOC_G_INPUT <VIDIOC_G_INPUT>` ioctl with a pointer to an integer where the driver
stores the number of the input, as in the struct
-:ref:`v4l2_input <v4l2-input>` ``index`` field. This ioctl will fail
+:c:type:`v4l2_input` ``index`` field. This ioctl will fail
only when there are no video inputs, returning ``EINVAL``.
To select a video input applications store the number of the desired
.. tabularcolumns:: |p{1.2cm}|p{3.0cm}|p{13.3cm}|
-.. _v4l2-jpegcompression:
+.. c:type:: v4l2_jpegcompression
.. flat-table:: struct v4l2_jpegcompression
:header-rows: 0
To query the attributes of a modulator applications initialize the
``index`` field and zero out the ``reserved`` array of a struct
-:ref:`v4l2_modulator <v4l2-modulator>` and call the
+:c:type:`v4l2_modulator` and call the
:ref:`VIDIOC_G_MODULATOR <VIDIOC_G_MODULATOR>` ioctl with a pointer to this structure. Drivers
fill the rest of the structure or return an ``EINVAL`` error code when the
index is out of bounds. To enumerate all modulators applications shall
.. tabularcolumns:: |p{2.9cm}|p{2.9cm}|p{5.8cm}|p{2.9cm}|p{3.0cm}|
-.. _v4l2-modulator:
+.. c:type:: v4l2_modulator
.. flat-table:: struct v4l2_modulator
:header-rows: 0
- ``capability``
- Modulator capability flags. No flags are defined for this field,
- the tuner flags in struct :ref:`v4l2_tuner <v4l2-tuner>` are
+ the tuner flags in struct :c:type:`v4l2_tuner` are
used accordingly. The audio flags indicate the ability to encode
audio subprograms. They will *not* change for example with the
current video standard.
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_modulator <v4l2-modulator>` ``index`` is
+ The struct :c:type:`v4l2_modulator` ``index`` is
out of bounds.
To query the current video output applications call the
:ref:`VIDIOC_G_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a pointer to an integer where the driver
stores the number of the output, as in the struct
-:ref:`v4l2_output <v4l2-output>` ``index`` field. This ioctl will
+:c:type:`v4l2_output` ``index`` field. This ioctl will
fail only when there are no video outputs, returning the ``EINVAL`` error
code.
To get and set the streaming parameters applications call the
:ref:`VIDIOC_G_PARM <VIDIOC_G_PARM>` and :ref:`VIDIOC_S_PARM <VIDIOC_G_PARM>` ioctl, respectively. They take a
-pointer to a struct :ref:`struct v4l2_streamparm <v4l2-streamparm>` which contains a
+pointer to a struct :c:type:`struct v4l2_streamparm <v4l2_streamparm>` which contains a
union holding separate parameters for input and output devices.
.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{3.5cm}|p{7.0cm}|
-.. _v4l2-streamparm:
+.. c:type:: v4l2_streamparm
.. flat-table:: struct v4l2_streamparm
:header-rows: 0
-
- The buffer (stream) type, same as struct
- :ref:`v4l2_format <v4l2-format>` ``type``, set by the
+ :c:type:`v4l2_format` ``type``, set by the
application. See :ref:`v4l2-buf-type`
- .. row 2
- .. row 3
-
- - struct :ref:`v4l2_captureparm <v4l2-captureparm>`
+ - struct :c:type:`v4l2_captureparm`
- ``capture``
- .. row 4
-
- - struct :ref:`v4l2_outputparm <v4l2-outputparm>`
+ - struct :c:type:`v4l2_outputparm`
- ``output``
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-captureparm:
+.. c:type:: v4l2_captureparm
.. flat-table:: struct v4l2_captureparm
:header-rows: 0
- .. row 3
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``timeperframe``
Applications store here the desired frame period, drivers return
the actual frame period, which must be greater or equal to the
nominal frame period determined by the current video standard
- (struct :ref:`v4l2_standard <v4l2-standard>` ``frameperiod``
+ (struct :c:type:`v4l2_standard` ``frameperiod``
field). Changing the video standard (also implicitly by switching
the video input) may reset this parameter to the nominal frame
period. To reset manually applications can just set this field to
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-outputparm:
+.. c:type:: v4l2_outputparm
.. flat-table:: struct v4l2_outputparm
:header-rows: 0
- .. row 3
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``timeperframe``
Applications store here the desired frame period, drivers return
the actual frame period, which must be greater or equal to the
nominal frame period determined by the current video standard
- (struct :ref:`v4l2_standard <v4l2-standard>` ``frameperiod``
+ (struct :c:type:`v4l2_standard` ``frameperiod``
field). Changing the video standard (also implicitly by switching
the video output) may reset this parameter to the nominal frame
period. To reset manually applications can just set this field to
The ioctls are used to query and configure selection rectangles.
To query the cropping (composing) rectangle set struct
-:ref:`v4l2_selection <v4l2-selection>` ``type`` field to the
+:c:type:`v4l2_selection` ``type`` field to the
respective buffer type. Do not use the multiplanar buffer types. Use
``V4L2_BUF_TYPE_VIDEO_CAPTURE`` instead of
``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and use
``V4L2_BUF_TYPE_VIDEO_OUTPUT`` instead of
``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``. The next step is setting the
-value of struct :ref:`v4l2_selection <v4l2-selection>` ``target``
+value of struct :c:type:`v4l2_selection` ``target``
field to ``V4L2_SEL_TGT_CROP`` (``V4L2_SEL_TGT_COMPOSE``). Please refer
to table :ref:`v4l2-selections-common` or :ref:`selection-api` for
additional targets. The ``flags`` and ``reserved`` fields of struct
-:ref:`v4l2_selection <v4l2-selection>` are ignored and they must be
+:c:type:`v4l2_selection` are ignored and they must be
filled with zeros. The driver fills the rest of the structure or returns
EINVAL error code if incorrect buffer type or target was used. If
cropping (composing) is not supported then the active rectangle is not
mutable and it is always equal to the bounds rectangle. Finally, the
-struct :ref:`v4l2_rect <v4l2-rect>` ``r`` rectangle is filled with
+struct :c:type:`v4l2_rect` ``r`` rectangle is filled with
the current cropping (composing) coordinates. The coordinates are
expressed in driver-dependent units. The only exception are rectangles
for images in raw formats, whose coordinates are always expressed in
pixels.
To change the cropping (composing) rectangle set the struct
-:ref:`v4l2_selection <v4l2-selection>` ``type`` field to the
+:c:type:`v4l2_selection` ``type`` field to the
respective buffer type. Do not use multiplanar buffers. Use
``V4L2_BUF_TYPE_VIDEO_CAPTURE`` instead of
``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``. Use
``V4L2_BUF_TYPE_VIDEO_OUTPUT`` instead of
``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``. The next step is setting the
-value of struct :ref:`v4l2_selection <v4l2-selection>` ``target`` to
+value of struct :c:type:`v4l2_selection` ``target`` to
``V4L2_SEL_TGT_CROP`` (``V4L2_SEL_TGT_COMPOSE``). Please refer to table
:ref:`v4l2-selections-common` or :ref:`selection-api` for additional
-targets. The struct :ref:`v4l2_rect <v4l2-rect>` ``r`` rectangle need
+targets. The struct :c:type:`v4l2_rect` ``r`` rectangle need
to be set to the desired active area. Field struct
-:ref:`v4l2_selection <v4l2-selection>` ``reserved`` is ignored and
+:c:type:`v4l2_selection` ``reserved`` is ignored and
must be filled with zeros. The driver may adjust coordinates of the
requested rectangle. An application may introduce constraints to control
-rounding behaviour. The struct :ref:`v4l2_selection <v4l2-selection>`
+rounding behaviour. The struct :c:type:`v4l2_selection`
``flags`` field must be set to one of the following:
- ``0`` - The driver can adjust the rectangle size freely and shall
following priority:
1. Satisfy constraints from struct
- :ref:`v4l2_selection <v4l2-selection>` ``flags``.
+ :c:type:`v4l2_selection` ``flags``.
2. Adjust width, height, left, and top to hardware limits and
alignments.
5. Keep horizontal and vertical offset as close as possible to original
ones.
-On success the struct :ref:`v4l2_rect <v4l2-rect>` ``r`` field
+On success the struct :c:type:`v4l2_rect` ``r`` field
contains the adjusted rectangle. When the parameters are unsuitable the
application may modify the cropping (composing) or image parameters and
repeat the cycle until satisfactory parameters have been negotiated. If
-.. _v4l2-selection:
+.. c:type:: v4l2_selection
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- .. row 4
- - struct :ref:`v4l2_rect <v4l2-rect>`
+ - struct :c:type:`v4l2_rect`
- ``r``
supported, or the ``flags`` argument is not valid.
ERANGE
- It is not possible to adjust struct :ref:`v4l2_rect <v4l2-rect>`
+ It is not possible to adjust struct :c:type:`v4l2_rect`
``r`` rectangle to satisfy all constraints given in the ``flags``
argument.
To find out which data services are supported by a sliced VBI capture or
output device, applications initialize the ``type`` field of a struct
-:ref:`v4l2_sliced_vbi_cap <v4l2-sliced-vbi-cap>`, clear the
+:c:type:`v4l2_sliced_vbi_cap`, clear the
``reserved`` array and call the :ref:`VIDIOC_G_SLICED_VBI_CAP <VIDIOC_G_SLICED_VBI_CAP>` ioctl. The
driver fills in the remaining fields or returns an ``EINVAL`` error code if
the sliced VBI API is unsupported or ``type`` is invalid.
to write-read, in Linux 2.6.19.
-.. _v4l2-sliced-vbi-cap:
+.. c:type:: v4l2_sliced_vbi_cap
.. tabularcolumns:: |p{1.2cm}|p{4.2cm}|p{4.1cm}|p{4.0cm}|p{4.0cm}|
:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a
:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`
can return a single flag or a set of flags as in struct
-:ref:`v4l2_standard <v4l2-standard>` field ``id``. The flags must be
+:c:type:`v4l2_standard` field ``id``. The flags must be
unambiguous such that they appear in only one enumerated
-:ref:`struct v4l2_standard <v4l2-standard>` structure.
+:c:type:`struct v4l2_standard <v4l2_standard>` structure.
:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it
does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When
To query the attributes of a tuner applications initialize the ``index``
field and zero out the ``reserved`` array of a struct
-:ref:`v4l2_tuner <v4l2-tuner>` and call the ``VIDIOC_G_TUNER`` ioctl
+:c:type:`v4l2_tuner` and call the ``VIDIOC_G_TUNER`` ioctl
with a pointer to this structure. Drivers fill the rest of the structure
or return an ``EINVAL`` error code when the index is out of bounds. To
enumerate all tuners applications shall begin at index zero,
.. tabularcolumns:: |p{1.3cm}|p{3.0cm}|p{6.6cm}|p{6.6cm}|
-.. _v4l2-tuner:
+.. c:type:: v4l2_tuner
.. cssclass:: longtable
If multiple frequency bands are supported, then ``capability`` is
the union of all ``capability`` fields of each struct
- :ref:`v4l2_frequency_band <v4l2-frequency-band>`.
+ :c:type:`v4l2_frequency_band`.
- .. row 5
received audio programs do not match.
Currently this is the only field of struct
- :ref:`struct v4l2_tuner <v4l2-tuner>` applications can change.
+ :c:type:`struct v4l2_tuner <v4l2_tuner>` applications can change.
- .. row 15
multi-standard because the video standard is automatically
determined from the frequency band.) The set of supported video
standards is available from the struct
- :ref:`v4l2_input <v4l2-input>` pointing to this tuner, see the
+ :c:type:`v4l2_input` pointing to this tuner, see the
description of ioctl :ref:`VIDIOC_ENUMINPUT`
for details. Only ``V4L2_TUNER_ANALOG_TV`` tuners can have this
capability.
:ref:`Generic Error Codes <gen-errors>` chapter.
EINVAL
- The struct :ref:`v4l2_tuner <v4l2-tuner>` ``index`` is out of
+ The struct :c:type:`v4l2_tuner` ``index`` is out of
bounds.
.. [#f1]
``V4L2_BUF_FLAG_NO_CACHE_INVALIDATE`` and
``V4L2_BUF_FLAG_NO_CACHE_CLEAN`` flags to skip the respective step.
-The :ref:`struct v4l2_buffer <v4l2-buffer>` structure is specified in
+The :c:type:`struct v4l2_buffer <v4l2_buffer>` structure is specified in
:ref:`buffer`.
The semantics depend on the selected I/O method.
To enqueue a buffer applications set the ``type`` field of a struct
-:ref:`v4l2_buffer <v4l2-buffer>` to the same buffer type as was
-previously used with struct :ref:`v4l2_format <v4l2-format>` ``type``
-and struct :ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``type``.
+:c:type:`v4l2_buffer` to the same buffer type as was
+previously used with struct :c:type:`v4l2_format` ``type``
+and struct :c:type:`v4l2_requestbuffers` ``type``.
Applications must also set the ``index`` field. Valid index numbers
range from zero to the number of buffers allocated with
:ref:`VIDIOC_REQBUFS` (struct
-:ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``count``) minus
-one. The contents of the struct :ref:`struct v4l2_buffer <v4l2-buffer>` returned
+:c:type:`v4l2_requestbuffers` ``count``) minus
+one. The contents of the struct :c:type:`struct v4l2_buffer <v4l2_buffer>` returned
by a :ref:`VIDIOC_QUERYBUF` ioctl will do as well.
When the buffer is intended for output (``type`` is
``V4L2_BUF_TYPE_VIDEO_OUTPUT``, ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``,
``reserved2`` and ``reserved`` fields must be set to 0. When using the
:ref:`multi-planar API <planar-apis>`, the ``m.planes`` field must
contain a userspace pointer to a filled-in array of struct
-:ref:`v4l2_plane <v4l2-plane>` and the ``length`` field must be set
+:c:type:`v4l2_plane` and the ``length`` field must be set
to the number of elements in that array.
To enqueue a :ref:`memory mapped <mmap>` buffer applications set the
``memory`` field to ``V4L2_MEMORY_USERPTR``, the ``m.userptr`` field to
the address of the buffer and ``length`` to its size. When the
multi-planar API is used, ``m.userptr`` and ``length`` members of the
-passed array of struct :ref:`v4l2_plane <v4l2-plane>` have to be used
+passed array of struct :c:type:`v4l2_plane` have to be used
instead. When ``VIDIOC_QBUF`` is called with a pointer to this structure
the driver sets the ``V4L2_BUF_FLAG_QUEUED`` flag and clears the
``V4L2_BUF_FLAG_MAPPED`` and ``V4L2_BUF_FLAG_DONE`` flags in the
``memory`` field to ``V4L2_MEMORY_DMABUF`` and the ``m.fd`` field to a
file descriptor associated with a DMABUF buffer. When the multi-planar
API is used the ``m.fd`` fields of the passed array of struct
-:ref:`v4l2_plane <v4l2-plane>` have to be used instead. When
+:c:type:`v4l2_plane` have to be used instead. When
``VIDIOC_QBUF`` is called with a pointer to this structure the driver
sets the ``V4L2_BUF_FLAG_QUEUED`` flag and clears the
``V4L2_BUF_FLAG_MAPPED`` and ``V4L2_BUF_FLAG_DONE`` flags in the
Applications call the ``VIDIOC_DQBUF`` ioctl to dequeue a filled
(capturing) or displayed (output) buffer from the driver's outgoing
queue. They just set the ``type``, ``memory`` and ``reserved`` fields of
-a struct :ref:`v4l2_buffer <v4l2-buffer>` as above, when
+a struct :c:type:`v4l2_buffer` as above, when
``VIDIOC_DQBUF`` is called with a pointer to this structure the driver
fills the remaining fields or returns an error code. The driver may also
set ``V4L2_BUF_FLAG_ERROR`` in the ``flags`` field. It indicates a
:ref:`open() <func-open>` function, ``VIDIOC_DQBUF`` returns
immediately with an ``EAGAIN`` error code when no buffer is available.
-The :ref:`struct v4l2_buffer <v4l2-buffer>` structure is specified in
+The :c:type:`struct v4l2_buffer <v4l2_buffer>` structure is specified in
:ref:`buffer`.
The hardware may be able to detect the current DV timings automatically,
similar to sensing the video standard. To do so, applications call
:ref:`VIDIOC_QUERY_DV_TIMINGS` with a pointer to a struct
-:ref:`v4l2_dv_timings <v4l2-dv-timings>`. Once the hardware detects
+:c:type:`v4l2_dv_timings`. Once the hardware detects
the timings, it will fill in the timings structure.
.. note::
been allocated with the :ref:`VIDIOC_REQBUFS` ioctl.
Applications set the ``type`` field of a struct
-:ref:`v4l2_buffer <v4l2-buffer>` to the same buffer type as was
-previously used with struct :ref:`v4l2_format <v4l2-format>` ``type``
-and struct :ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``type``,
+:c:type:`v4l2_buffer` to the same buffer type as was
+previously used with struct :c:type:`v4l2_format` ``type``
+and struct :c:type:`v4l2_requestbuffers` ``type``,
and the ``index`` field. Valid index numbers range from zero to the
number of buffers allocated with
:ref:`VIDIOC_REQBUFS` (struct
-:ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``count``) minus
+:c:type:`v4l2_requestbuffers` ``count``) minus
one. The ``reserved`` and ``reserved2`` fields must be set to 0. When
using the :ref:`multi-planar API <planar-apis>`, the ``m.planes``
field must contain a userspace pointer to an array of struct
-:ref:`v4l2_plane <v4l2-plane>` and the ``length`` field has to be set
+:c:type:`v4l2_plane` and the ``length`` field has to be set
to the number of elements in that array. After calling
:ref:`VIDIOC_QUERYBUF` with a pointer to this structure drivers return an
error code or fill the rest of the structure.
device memory, the ``length`` field its size. For the multi-planar API,
fields ``m.mem_offset`` and ``length`` in the ``m.planes`` array
elements will be used instead and the ``length`` field of struct
-:ref:`v4l2_buffer <v4l2-buffer>` is set to the number of filled-in
+:c:type:`v4l2_buffer` is set to the number of filled-in
array elements. The driver may or may not set the remaining fields and
flags, they are meaningless in this context.
-The :ref:`struct v4l2_buffer <v4l2-buffer>` structure is specified in
+The :c:type:`struct v4l2_buffer <v4l2_buffer>` structure is specified in
:ref:`buffer`.
All V4L2 devices support the ``VIDIOC_QUERYCAP`` ioctl. It is used to
identify kernel devices compatible with this specification and to obtain
information about driver and hardware capabilities. The ioctl takes a
-pointer to a struct :ref:`v4l2_capability <v4l2-capability>` which is
+pointer to a struct :c:type:`v4l2_capability` which is
filled by the driver. When the driver is not compatible with this
specification the ioctl returns an ``EINVAL`` error code.
.. tabularcolumns:: |p{1.5cm}|p{2.5cm}|p{13cm}|
-.. _v4l2-capability:
+.. c:type:: v4l2_capability
.. flat-table:: struct v4l2_capability
:header-rows: 0
- 0x00200000
- The device supports the struct
- :ref:`v4l2_pix_format <v4l2-pix-format>` extended fields.
+ :c:type:`v4l2_pix_format` extended fields.
- .. row 22
:ref:`Generic Error Codes <gen-errors>` chapter.
.. [#f1]
- The struct :ref:`v4l2_framebuffer <v4l2-framebuffer>` lacks an
+ The struct :c:type:`v4l2_framebuffer` lacks an
enum :ref:`v4l2_buf_type <v4l2-buf-type>` field, therefore the
type of overlay is implied by the driver capabilities.
pass a string of length 8 to
:ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` you need to
set the ``size`` field of struct
- :ref:`v4l2_ext_control <v4l2-ext-control>` to 9. For
+ :c:type:`v4l2_ext_control` to 9. For
:ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` you can set
the ``size`` field to ``maximum`` + 1. Which character encoding is
used will depend on the string control itself and should be part
- This control has a pointer type, so its value has to be accessed
using one of the pointer fields of struct
- :ref:`v4l2_ext_control <v4l2-ext-control>`. This flag is set
+ :c:type:`v4l2_ext_control`. This flag is set
for controls that are an array, string, or have a compound type.
In all cases you have to set a pointer to memory containing the
payload of the control.
allocation.
To allocate device buffers applications initialize all fields of the
-:ref:`struct v4l2_requestbuffers <v4l2-requestbuffers>` structure. They set the ``type``
+:c:type:`struct v4l2_requestbuffers <v4l2_requestbuffers>` structure. They set the ``type``
field to the respective stream or buffer type, the ``count`` field to
the desired number of buffers, ``memory`` must be set to the requested
I/O method and the ``reserved`` array must be zeroed. When the ioctl is
:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>`.
-.. _v4l2-requestbuffers:
+.. c:type:: v4l2_requestbuffers
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- ``type``
- Type of the stream or buffers, this is the same as the struct
- :ref:`v4l2_format <v4l2-format>` ``type`` field. See
+ :c:type:`v4l2_format` ``type`` field. See
:ref:`v4l2-buf-type` for valid values.
- .. row 3
applications initialize the ``tuner``, ``type``, ``seek_upward``,
``wrap_around``, ``spacing``, ``rangelow`` and ``rangehigh`` fields, and
zero out the ``reserved`` array of a struct
-:ref:`v4l2_hw_freq_seek <v4l2-hw-freq-seek>` and call the
+:c:type:`v4l2_hw_freq_seek` and call the
``VIDIOC_S_HW_FREQ_SEEK`` ioctl with a pointer to this structure.
The ``rangelow`` and ``rangehigh`` fields can be set to a non-zero value
to tell the driver to search a specific band. If the struct
-:ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has the
+:c:type:`v4l2_tuner` ``capability`` field has the
``V4L2_TUNER_CAP_HWSEEK_PROG_LIM`` flag set, these values must fall
within one of the bands returned by
:ref:`VIDIOC_ENUM_FREQ_BANDS`. If the
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-hw-freq-seek:
+.. c:type:: v4l2_hw_freq_seek
.. flat-table:: struct v4l2_hw_freq_seek
:header-rows: 0
- ``tuner``
- The tuner index number. This is the same value as in the struct
- :ref:`v4l2_input <v4l2-input>` ``tuner`` field and the struct
- :ref:`v4l2_tuner <v4l2-tuner>` ``index`` field.
+ :c:type:`v4l2_input` ``tuner`` field and the struct
+ :c:type:`v4l2_tuner` ``index`` field.
- .. row 2
- ``type``
- The tuner type. This is the same value as in the struct
- :ref:`v4l2_tuner <v4l2-tuner>` ``type`` field. See
+ :c:type:`v4l2_tuner` ``type`` field. See
:ref:`v4l2-tuner-type`
- .. row 3
- ``wrap_around``
- If non-zero, wrap around when at the end of the frequency range,
- else stop seeking. The struct :ref:`v4l2_tuner <v4l2-tuner>`
+ else stop seeking. The struct :c:type:`v4l2_tuner`
``capability`` field will tell you what the hardware supports.
- .. row 5
- If non-zero, the lowest tunable frequency of the band to search in
units of 62.5 kHz, or if the struct
- :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has the
+ :c:type:`v4l2_tuner` ``capability`` field has the
``V4L2_TUNER_CAP_LOW`` flag set, in units of 62.5 Hz or if the
- struct :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has
+ struct :c:type:`v4l2_tuner` ``capability`` field has
the ``V4L2_TUNER_CAP_1HZ`` flag set, in units of 1 Hz. If
``rangelow`` is zero a reasonable default value is used.
- If non-zero, the highest tunable frequency of the band to search
in units of 62.5 kHz, or if the struct
- :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has the
+ :c:type:`v4l2_tuner` ``capability`` field has the
``V4L2_TUNER_CAP_LOW`` flag set, in units of 62.5 Hz or if the
- struct :ref:`v4l2_tuner <v4l2-tuner>` ``capability`` field has
+ struct :c:type:`v4l2_tuner` ``capability`` field has
the ``V4L2_TUNER_CAP_1HZ`` flag set, in units of 1 Hz. If
``rangehigh`` is zero a reasonable default value is used.
Both ioctls take a pointer to an integer, the desired buffer or stream
type. This is the same as struct
-:ref:`v4l2_requestbuffers <v4l2-requestbuffers>` ``type``.
+:c:type:`v4l2_requestbuffers` ``type``.
If ``VIDIOC_STREAMON`` is called when streaming is already in progress,
or if ``VIDIOC_STREAMOFF`` is called when streaming is already stopped,
- .. row 6
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``interval``
- .. row 3
- - struct :ref:`v4l2_rect <v4l2-rect>`
+ - struct :c:type:`v4l2_rect`
- ``rect``
- .. row 2
- - struct :ref:`v4l2_fract <v4l2-fract>`
+ - struct :c:type:`v4l2_fract`
- ``interval``
- .. row 5
- - struct :ref:`v4l2_rect <v4l2-rect>`
+ - struct :c:type:`v4l2_rect`
- ``r``
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
-.. _v4l2-event-subscription:
+.. c:type:: v4l2_event_subscription
.. flat-table:: struct v4l2_event_subscription
:header-rows: 0
projects / cascardo / linux.git / commitdiff