.. 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_FMT:

*********************
ioctl VIDIOC_ENUM_FMT
*********************

Name
====

VIDIOC_ENUM_FMT - Enumerate image formats


Synopsis
========

.. c:function:: int ioctl( int fd, VIDIOC_ENUM_FMT, struct v4l2_fmtdesc *argp )
    :name: VIDIOC_ENUM_FMT


Arguments
=========

``fd``
    File descriptor returned by :ref:`open() <func-open>`.

``argp``
    Pointer to struct :c:type:`v4l2_fmtdesc`.


Description
===========

To enumerate image formats applications initialize the ``type`` and
``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
one until ``EINVAL`` is returned.

.. note::

   After switching input or output the list of enumerated image
   formats may be different.


.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|

.. c:type:: v4l2_fmtdesc

.. flat-table:: struct v4l2_fmtdesc
    :header-rows:  0
    :stub-columns: 0
    :widths:       1 1 2

    * - __u32
      - ``index``
      - Number of the format in the enumeration, set by the application.
	This is in no way related to the ``pixelformat`` field.
    * - __u32
      - ``type``
      - Type of the data stream, set by the application. Only these types
	are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``,
	``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``,
	``V4L2_BUF_TYPE_VIDEO_OUTPUT``,
	``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``,
	``V4L2_BUF_TYPE_VIDEO_OVERLAY``,
	``V4L2_BUF_TYPE_SDR_CAPTURE``,
	                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        