115 lines
3.7 KiB
ReStructuredText
115 lines
3.7 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
|
|
.. document under the terms of the GNU Free Documentation License,
|
|
.. Version 1.1 or any later version published by the Free Software
|
|
.. Foundation, with no Invariant Sections, no Front-Cover Texts
|
|
.. and no Back-Cover Texts. A copy of the license is included at
|
|
.. Documentation/media/uapi/fdl-appendix.rst.
|
|
..
|
|
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
|
|
|
|
.. _VIDIOC_ENUM_DV_TIMINGS:
|
|
|
|
***********************************************************
|
|
ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS
|
|
***********************************************************
|
|
|
|
Name
|
|
====
|
|
|
|
VIDIOC_ENUM_DV_TIMINGS - VIDIOC_SUBDEV_ENUM_DV_TIMINGS - Enumerate supported Digital Video timings
|
|
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp )
|
|
:name: VIDIOC_ENUM_DV_TIMINGS
|
|
|
|
.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_ENUM_DV_TIMINGS, struct v4l2_enum_dv_timings *argp )
|
|
:name: VIDIOC_SUBDEV_ENUM_DV_TIMINGS
|
|
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :ref:`open() <func-open>`.
|
|
|
|
``argp``
|
|
Pointer to struct :c:type:`v4l2_enum_dv_timings`.
|
|
|
|
|
|
Description
|
|
===========
|
|
|
|
While some DV receivers or transmitters support a wide range of timings,
|
|
others support only a limited number of timings. With this ioctl
|
|
applications can enumerate a list of known supported timings. Call
|
|
:ref:`VIDIOC_DV_TIMINGS_CAP` to check if it
|
|
also supports other standards or even custom timings that are not in
|
|
this list.
|
|
|
|
To query the available timings, applications initialize the ``index``
|
|
field, set the ``pad`` field to 0, zero the reserved array of struct
|
|
: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
|
|
DV timings, applications shall begin at index zero, incrementing by one
|
|
until the driver returns ``EINVAL``.
|
|
|
|
.. note::
|
|
|
|
Drivers may enumerate a different set of DV timings after
|
|
switching the video input or output.
|
|
|
|
When implemented by the driver DV timings of subdevices can be queried
|
|
by calling the ``VIDIOC_SUBDEV_ENUM_DV_TIMINGS`` ioctl directly on a
|
|
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
|
|
: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.
|
|
|
|
|
|
.. c:type:: v4l2_enum_dv_timings
|
|
|
|
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
|
|
|
|
.. flat-table:: struct v4l2_enum_dv_timings
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
:widths: 1 1 2
|
|
|
|
* - __u32
|
|
- ``index``
|
|
- Number of the DV timings, set by the application.
|
|
* - __u32
|
|
- ``pad``
|
|
- Pad number as reported by the media controller API. This field is
|
|
only used when operating on a subdevice node. When operating on a
|
|
video node applications must set this field to zero.
|
|
* - __u32
|
|
- ``reserved``\ [2]
|
|
- Reserved for future extensions. Drivers and applications must set
|
|
the array to zero.
|
|
* - struct :c:type:`v4l2_dv_timings`
|
|
- ``timings``
|
|
- The timings.
|
|
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success 0 is returned, on error -1 and the ``errno`` variable is set
|
|
appropriately. The generic error codes are described at the
|
|
:ref:`Generic Error Codes <gen-errors>` chapter.
|
|
|
|
EINVAL
|
|
The struct :c:type:`v4l2_enum_dv_timings`
|
|
``index`` is out of bounds or the ``pad`` number is invalid.
|
|
|
|
ENODATA
|
|
Digital video presets are not supported for this input or output.
|