media: hist-v4l2.rst: remove :c:`type` from structs and enums

Codec API was released.

1998-11-08: Many minor changes. Most symbols have been renamed. Some

material changes to struct :c:type:`v4l2_capability`.

material changes to struct v4l2_capability.

1998-11-12: The read/write directon of some ioctls was misdefined.

to simplify the API, while making it more extensible and following

common Linux driver API conventions.

1. Some typos in ``V4L2_FMT_FLAG`` symbols were fixed. struct

   :c:type:`v4l2_clip` was changed for compatibility with

   v4l. (1999-08-30)

1. Some typos in ``V4L2_FMT_FLAG`` symbols were fixed. struct v4l2_clip

   was changed for compatibility with v4l. (1999-08-30)

2. ``V4L2_TUNER_SUB_LANG1`` was added. (1999-09-05)

   This change obsoletes the following ioctls: ``VIDIOC_S_INFMT``,

   ``VIDIOC_G_INFMT``, ``VIDIOC_S_OUTFMT``, ``VIDIOC_G_OUTFMT``,

   ``VIDIOC_S_VBIFMT`` and ``VIDIOC_G_VBIFMT``. The image format

   structure struct :c:type:`v4l2_format` was renamed to struct

   :c:type:`v4l2_pix_format`, while struct

   :c:type:`v4l2_format` is now the envelopping structure

   struct v4l2_format was renamed to struct v4l2_pix_format, while

   struct 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

   :c:type:`v4l2_streamparm` selects the respective

   union member.

   ``VIDIOC_S_OUTPARM``. A ``type`` field in the new struct v4l2_streamparm

   selects the respective union member.

   This change obsoletes the ``VIDIOC_G_OUTPARM`` and

   ``VIDIOC_S_OUTPARM`` ioctls.

   categories might have a greater separation, or may even appear in

   separate windows.

7. The struct :c:type:`v4l2_buffer` ``timestamp`` was

7. The struct 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

   v4l2_masterclock_gettime() function (used only by drivers) to

   return a 64-bit integer.

8. A ``sequence`` field was added to struct

   :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.

8. A ``sequence`` field was added to struct 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 :c:type:`v4l2_vbi_format` the

1999-12-23: In struct v4l2_vbi_format the

``reserved1`` field became ``offset``. Previously drivers were required

to clear the ``reserved1`` field.

compatibility* as the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` and

:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctls may fail now if the

struct ``v4l2_fmt`` ``type`` field does not contain

``V4L2_BUF_TYPE_VBI``. In the documentation of the struct

:c:type:`v4l2_vbi_format` ``offset`` field the

ambiguous phrase "rising edge" was changed to "leading edge".

``V4L2_BUF_TYPE_VBI``. In the documentation of the struct v4l2_vbi_format`,

the ``offset`` field the ambiguous phrase "rising edge" was changed to

"leading edge".

V4L2 Version 0.20 2000-11-23

============================

    until the application attempts to initiate a data exchange, see

    :ref:`open`.

3.  The struct :c:type:`v4l2_capability` changed

3.  The struct 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 :c:type:`v4l2_input` the ``assoc_audio``

4.  In struct 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 :c:type:`v4l2_output` lost its

    Accordingly struct v4l2_output lost its

    ``capability`` and ``assoc_audio`` fields. ``audioset``,

    ``modulator`` and ``std`` where added instead.

5.  The struct :c:type:`v4l2_audio` field ``audio`` was

5.  The struct 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.

    where removed. This can be easily implemented using controls.

    (However the same applies to AVL which is still there.)

    Again for consistency the struct

    :c:type:`v4l2_audioout` field ``audio`` was renamed

    Again for consistency the struct v4l2_audioout field ``audio`` was renamed

    to ``index``.

6.  The struct :c:type:`v4l2_tuner` ``input`` field was

6.  The struct 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

    :c:type:`v4l2_input`. A ``type`` field was added.

    simple set (more about this below) and moved into struct v4l2_input.

    A ``type`` field was added.

    Accordingly in struct :c:type:`v4l2_modulator` the

    Accordingly in struct v4l2_modulator the

    ``output`` was replaced by an ``index`` field.

    In struct :c:type:`v4l2_frequency` the ``port``

    In struct 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 :c:type:`v4l2_standard` an

    capability. In struct 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 ``v4l2_enumstd`` ceased to be.

    :ref:`VIDIOC_ENUMSTD` now takes a pointer to a

    struct :c:type:`v4l2_standard` directly. The

    struct v4l2_standard directly. The

    information which standards are supported by a particular video

    input or output moved into struct :c:type:`v4l2_input`

    and struct :c:type:`v4l2_output` fields named ``std``,

    input or output moved into struct v4l2_input

    and struct 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 :c:type:`v4l2_format` the ``fmt`` union was

    extended to contain struct :c:type:`v4l2_window`. All

    In struct v4l2_format the ``fmt`` union was

    extended to contain struct 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

    removed. The ``type`` field changed to type enum

    :c:type:`v4l2_buf_type` and the buffer type names

    changed as follows.

    removed. The ``type`` field changed to type enum v4l2_buf_type and

    the buffer type names changed as follows.

	:stub-columns: 0

	* - Old defines

	  - enum :c:type:`v4l2_buf_type`

	  - enum v4l2_buf_type

	* - ``V4L2_BUF_TYPE_CAPTURE``

	  - ``V4L2_BUF_TYPE_VIDEO_CAPTURE``

	* - ``V4L2_BUF_TYPE_CODECIN``

	* - ``V4L2_BUF_TYPE_PRIVATE_BASE``

	  - ``V4L2_BUF_TYPE_PRIVATE`` (but this is deprecated)

10. In struct v4l2_fmtdesc a enum v4l2_buf_type field named ``type`` was

    added as in struct 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``.

10. In struct :c:type:`v4l2_fmtdesc` a enum

    :c:type:`v4l2_buf_type` field named ``type`` was

    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 :c:type:`v4l2_pix_format` the ``depth``

11. In struct 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

    Since the remaining flags were replaced as well, the ``flags`` field

    itself was removed.

    The interlace flags were replaced by a enum

    :c:type:`v4l2_field` value in a newly added ``field``

    field.

    The interlace flags were replaced by a enum v4l2_field value in a

    newly added ``field`` field.

    .. flat-table::

	:header-rows:  1

	:stub-columns: 0

	* - Old flag

	  - enum :c:type:`v4l2_field`

	  - enum v4l2_field

	* - ``V4L2_FMT_FLAG_NOT_INTERLACED``

	  - ?

	* - ``V4L2_FMT_FLAG_INTERLACED`` = ``V4L2_FMT_FLAG_COMBINED``

	* - ``-``

	  - ``V4L2_FIELD_ALTERNATE``

    The color space flags were replaced by a enum

    :c:type:`v4l2_colorspace` value in a newly added

    ``colorspace`` field, where one of ``V4L2_COLORSPACE_SMPTE170M``,

    ``V4L2_COLORSPACE_BT878``, ``V4L2_COLORSPACE_470_SYSTEM_M`` or

    The color space flags were replaced by a enum v4l2_colorspace value in

    a newly added ``colorspace`` field, where one of

    ``V4L2_COLORSPACE_SMPTE170M``, ``V4L2_COLORSPACE_BT878``,

    ``V4L2_COLORSPACE_470_SYSTEM_M`` or

    ``V4L2_COLORSPACE_470_SYSTEM_BG`` replaces ``V4L2_FMT_CS_601YUV``.

12. In struct :c:type:`v4l2_requestbuffers` the

    ``type`` field was properly defined as enum

    :c:type:`v4l2_buf_type`. Buffer types changed as

    mentioned above. A new ``memory`` field of type enum

    :c:type:`v4l2_memory` was added to distinguish between

12. In struct v4l2_requestbuffers the

    ``type`` field was properly defined as enum v4l2_buf_type. Buffer types

    changed as mentioned above. A new ``memory`` field of type

    enum v4l2_memory was added to distinguish between

    I/O methods using buffers allocated by the driver or the

    application. See :ref:`io` for details.

13. In struct :c:type:`v4l2_buffer` the ``type`` field was

    properly defined as enum :c:type:`v4l2_buf_type`.

13. In struct v4l2_buffer the ``type`` field was

    properly defined as enum v4l2_buf_type.

    Buffer types changed as mentioned above. A ``field`` field of type

    enum :c:type:`v4l2_field` was added to indicate if a

    enum v4l2_field was added to indicate if a

    buffer contains a top or bottom field. The old field flags were

    removed. Since no unadjusted system time clock was added to the

    kernel as planned, the ``timestamp`` field changed back from type

    stamp_t, an unsigned 64 bit integer expressing the sample time in

    nanoseconds, to struct :c:type:`timeval`. With the addition

    nanoseconds, to struct timeval. With the addition

    of a second memory mapping method the ``offset`` field moved into

    union ``m``, and a new ``memory`` field of type enum

    :c:type:`v4l2_memory` was added to distinguish between

    union ``m``, and a new ``memory`` field of type enum v4l2_memory

    was added to distinguish between

    I/O methods. See :ref:`io` for details.

    The ``V4L2_BUF_REQ_CONTIG`` flag was used by the V4L compatibility

    indeed allocated in device memory rather than DMA-able system

    memory. It was barely useful and so was removed.

14. In struct :c:type:`v4l2_framebuffer` the

14. In struct 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 :c:type:`v4l2_clip` the ``x``, ``y``,

15. In struct v4l2_clip the ``x``, ``y``,

    ``width`` and ``height`` field moved into a ``c`` substructure of

    type struct :c:type:`v4l2_rect`. The ``x`` and ``y``

    type struct v4l2_rect. The ``x`` and ``y``

    fields were renamed to ``left`` and ``top``, i. e. offsets to a

    context dependent origin.

16. In struct :c:type:`v4l2_window` the ``x``, ``y``,

16. In struct v4l2_window the ``x``, ``y``,

    ``width`` and ``height`` field moved into a ``w`` substructure as

    above. A ``field`` field of type :c:type:`v4l2_field` was added to

    above. A ``field`` field of type enum v4l2_field was added to

    distinguish between field and frame (interlaced) overlay.

17. The digital zoom interface, including struct ``v4l2_zoomcap``,

    struct ``v4l2_zoom``, ``V4L2_ZOOM_NONCAP`` and

    ``V4L2_ZOOM_WHILESTREAMING`` was replaced by a new cropping and

    scaling interface. The previously unused

    struct :c:type:`v4l2_cropcap` and struct :c:type:`v4l2_crop`

    struct v4l2_cropcap and struct v4l2_crop

    where redefined for this purpose. See :ref:`crop` for details.

18. In struct :c:type:`v4l2_vbi_format` the

18. In struct 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 :c:type:`v4l2_captureparm` the type of

    the ``timeperframe`` field changed from unsigned long to struct

    :c:type:`v4l2_fract`. This allows the accurate

19. In struct v4l2_captureparm the type of

    the ``timeperframe`` field changed from unsigned long to

    struct 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

    :c:type:`v4l2_outputparm`.

    Similar changes were made to struct v4l2_outputparm.

20. The 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 :c:type:`v4l2_buffer` structure. Purpose of this

   struct v4l2_buffer. 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 :c:type:`v4l2_buffer` ``memory`` field. It was

   struct v4l2_buffer ``memory`` field. It was

   also missing from examples. Also on the ``VIDIOC_DQBUF`` page the ``EIO``

   error code was not documented.

V4L2 spec erratum 2006-01-10

============================

1. The ``V4L2_IN_ST_COLOR_KILL`` flag in struct

   :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.)

1. The ``V4L2_IN_ST_COLOR_KILL`` flag in struct 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.)

2. :ref:`VIDIOC_S_PARM <VIDIOC_G_PARM>` is a write-read ioctl, not

   write-only as stated on its reference page. The ioctl changed in 2003

V4L2 spec erratum 2006-02-03

============================

1. In struct :c:type:`v4l2_captureparm` and struct

   :c:type:`v4l2_outputparm` the ``timeperframe``

1. In struct v4l2_captureparm and struct v4l2_outputparm the ``timeperframe``

   field gives the time in seconds, not microseconds.

V4L2 spec erratum 2006-02-04

============================

1. The ``clips`` field in struct :c:type:`v4l2_window`

   must point to an array of struct :c:type:`v4l2_clip`, not

1. The ``clips`` field in struct v4l2_window

   must point to an array of struct v4l2_clip, not

   a linked list, because drivers ignore the

   struct :c:type:`v4l2_clip`. ``next`` pointer.

   struct v4l2_clip. ``next`` pointer.

V4L2 in Linux 2.6.17

====================

   ``V4L2_BUF_TYPE_SLICED_VBI_OUTPUT`` of the sliced VBI interface were

   not mentioned along with other buffer types.

2. In :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` it was clarified that the struct

   :c:type:`v4l2_audio` ``mode`` field is a flags field.

2. In :ref:`VIDIOC_G_AUDIO <VIDIOC_G_AUDIO>` it was clarified that the

   struct 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

   :c:type:`v4l2_frequency` before calling

4. In :ref:`VIDIOC_G_FREQUENCY <VIDIOC_G_FREQUENCY>` it was clarified that

   applications must initialize the tuner ``type`` field of

   struct v4l2_frequency before calling

   :ref:`VIDIOC_S_FREQUENCY <VIDIOC_G_FREQUENCY>`.

5. The ``reserved`` array in struct

   :c:type:`v4l2_requestbuffers` has 2 elements,

5. The ``reserved`` array in struct v4l2_requestbuffers has 2 elements,

   not 32.

6. In :ref:`output` and :ref:`raw-vbi` the device file names

   flag to skip unsupported controls with

   :ref:`VIDIOC_QUERYCTRL`, new control types

   ``V4L2_CTRL_TYPE_INTEGER64`` and ``V4L2_CTRL_TYPE_CTRL_CLASS``

   (:c:type:`v4l2_ctrl_type`), and new control flags

   (enum v4l2_ctrl_type), and new control flags

   ``V4L2_CTRL_FLAG_READ_ONLY``, ``V4L2_CTRL_FLAG_UPDATE``,

   ``V4L2_CTRL_FLAG_INACTIVE`` and ``V4L2_CTRL_FLAG_SLIDER``

   (:ref:`control-flags`). See :ref:`extended-controls` for details.

V4L2 in Linux 2.6.19

====================

1. In struct :c:type:`v4l2_sliced_vbi_cap` a

1. In struct 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

====================

1. Two new field orders ``V4L2_FIELD_INTERLACED_TB`` and

   ``V4L2_FIELD_INTERLACED_BT`` were added. See :c:type:`v4l2_field` for

   ``V4L2_FIELD_INTERLACED_BT`` were added. See enum v4l2_field for

   details.

2. Three new clipping/blending methods with a global or straight or

   See the description of the :ref:`VIDIOC_G_FBUF <VIDIOC_G_FBUF>`

   and :ref:`VIDIOC_S_FBUF <VIDIOC_G_FBUF>` ioctls for details.

   A new ``global_alpha`` field was added to

   :c:type:`v4l2_window`, extending the structure. This

   may *break compatibility* with applications using a

   struct :c:type:`v4l2_window` directly. However the

   A new ``global_alpha`` field was added to struct v4l2_window,

   extending the structure. This may **break compatibility** with

   applications using a struct v4l2_window directly. However the

   :ref:`VIDIOC_G/S/TRY_FMT <VIDIOC_G_FMT>` ioctls, which take a

   pointer to a :c:type:`v4l2_format` parent structure

   pointer to a struct v4l2_format parent structure

   with padding bytes at the end, are not affected.

3. The format of the ``chromakey`` field in struct

   :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.

3. The format of the ``chromakey`` field in struct 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 2.6.24

V4L2 in Linux 3.6

=================

1. Replaced ``input`` in struct :c:type:`v4l2_buffer` by

1. Replaced ``input`` in struct v4l2_buffer by

   ``reserved2`` and removed ``V4L2_BUF_FLAG_INPUT``.

2. Added V4L2_CAP_VIDEO_M2M and V4L2_CAP_VIDEO_M2M_MPLANE

=================

1. Added timestamp types to ``flags`` field in

   struct :c:type:`v4l2_buffer`. See :ref:`buffer-flags`.

   struct v4l2_buffer. See :ref:`buffer-flags`.

2. Added ``V4L2_EVENT_CTRL_CH_RANGE`` control event changes flag. See

   :ref:`ctrl-changes-flags`.

V4L2 in Linux 3.14

==================

1. In struct :c:type:`v4l2_rect`, the type of ``width`` and

1. In struct v4l2_rect, the type of ``width`` and

   ``height`` fields changed from _s32 to _u32.

V4L2 in Linux 3.17

==================

1. Extended struct :c:type:`v4l2_pix_format`. Added

1. Extended struct v4l2_pix_format. Added

   format flags.

2. Added compound control types and

V4L2 in Linux 3.19

==================

1. Rewrote Colorspace chapter, added new enum

   :c:type:`v4l2_ycbcr_encoding` and enum

   :c:type:`v4l2_quantization` fields to struct

   :c:type:`v4l2_pix_format`, struct

   :c:type:`v4l2_pix_format_mplane` and

   struct :c:type:`v4l2_mbus_framefmt`.

1. Rewrote Colorspace chapter, added new enum v4l2_ycbcr_encoding

   and enum v4l2_quantization fields to struct v4l2_pix_format,

   struct v4l2_pix_format_mplane and struct v4l2_mbus_framefmt.

V4L2 in Linux 4.4

=================