.. 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() `. ``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``, ``V4L2_BUF_TYPE_SDR_OUTPUT`` and ``V4L2_BUF_TYPE_META_CAPTURE``. See :c:type:`v4l2_buf_type`. * - __u32 - ``flags`` - See :ref:`fmtdesc-flags` * - __u8 - ``description``\ [32] - Description of the format, a NUL-terminated ASCII string. This information is intended for the user, for example: "YUV 4:2:2". * - __u32 - ``pixelformat`` - The image format identifier. This is a four character code as computed by the v4l2_fourcc() macro: * - :cspan:`2` .. _v4l2-fourcc: ``#define v4l2_fourcc(a,b,c,d)`` ``(((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24))`` Several image formats are already defined by this specification in :ref:`pixfmt`. .. attention:: These codes are not the same as those used in the Windows world. * - __u32 - ``reserved``\ [4] - Reserved for future extensions. Drivers must set the array to zero. .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| .. _fmtdesc-flags: .. flat-table:: Image Format Description Flags :header-rows: 0 :stub-columns: 0 :widths: 3 1 4 * - ``V4L2_FMT_FLAG_COMPRESSED`` - 0x0001 - This is a compressed format. * - ``V4L2_FMT_FLAG_EMULATED`` - 0x0002 - This format is not native to the device but emulated through software (usually libv4l2), where possible try to use a native format instead for better performance. 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 ` chapter. EINVAL The struct :c:type:`v4l2_fmtdesc` ``type`` is not supported or the ``index`` is out of bounds.