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Diffstat (limited to 'Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst | 92 |
1 files changed, 70 insertions, 22 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst index a53dd3d7f7e2..000c154b0f98 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst @@ -1,11 +1,5 @@ -.. 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/userspace-api/media/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L .. _VIDIOC_ENUM_FMT: @@ -18,24 +12,22 @@ 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 +.. c:macro:: VIDIOC_ENUM_FMT +``int ioctl(int fd, VIDIOC_ENUM_FMT, struct v4l2_fmtdesc *argp)`` Arguments ========= ``fd`` - File descriptor returned by :ref:`open() <func-open>`. + File descriptor returned by :c:func:`open()`. ``argp`` Pointer to struct :c:type:`v4l2_fmtdesc`. - Description =========== @@ -79,10 +71,11 @@ the ``mbus_code`` field is handled differently: formats shall not depend on the active configuration of the video device or device pipeline. +.. c:type:: v4l2_fmtdesc -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| +.. cssclass:: longtable -.. c:type:: v4l2_fmtdesc +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| .. flat-table:: struct v4l2_fmtdesc :header-rows: 0 @@ -144,8 +137,9 @@ the ``mbus_code`` field is handled differently: zero. +.. tabularcolumns:: |p{8.4cm}|p{1.8cm}|p{7.1cm}| -.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| +.. cssclass:: longtable .. _fmtdesc-flags: @@ -167,18 +161,72 @@ the ``mbus_code`` field is handled differently: - The hardware decoder for this compressed bytestream format (aka coded format) is capable of parsing a continuous bytestream. Applications do not need to parse the bytestream themselves to find the boundaries - between frames/fields. This flag can only be used in combination with - the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to compressed + between frames/fields. + + This flag can only be used in combination with the + ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to compressed formats only. This flag is valid for stateful decoders only. * - ``V4L2_FMT_FLAG_DYN_RESOLUTION`` - 0x0008 - Dynamic resolution switching is supported by the device for this compressed bytestream format (aka coded format). It will notify the user via the event ``V4L2_EVENT_SOURCE_CHANGE`` when changes in the video - parameters are detected. This flag can only be used in combination - with the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to - compressed formats only. It is also only applies to stateful codecs. - + parameters are detected. + + This flag can only be used in combination with the + ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to + compressed formats only. This flag is valid for stateful codecs only. + * - ``V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL`` + - 0x0010 + - The hardware encoder supports setting the ``CAPTURE`` coded frame + interval separately from the ``OUTPUT`` raw frame interval. + Setting the ``OUTPUT`` raw frame interval with :ref:`VIDIOC_S_PARM <VIDIOC_G_PARM>` + also sets the ``CAPTURE`` coded frame interval to the same value. + If this flag is set, then the ``CAPTURE`` coded frame interval can be + set to a different value afterwards. This is typically used for + offline encoding where the ``OUTPUT`` raw frame interval is used as + a hint for reserving hardware encoder resources and the ``CAPTURE`` coded + frame interval is the actual frame rate embedded in the encoded video + stream. + + This flag can only be used in combination with the + ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to + compressed formats only. This flag is valid for stateful encoders only. + * - ``V4L2_FMT_FLAG_CSC_COLORSPACE`` + - 0x0020 + - The driver allows the application to try to change the default + colorspace. This flag is relevant only for capture devices. + The application can ask to configure the colorspace of the capture device + when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set. + * - ``V4L2_FMT_FLAG_CSC_XFER_FUNC`` + - 0x0040 + - The driver allows the application to try to change the default + transfer function. This flag is relevant only for capture devices. + The application can ask to configure the transfer function of the capture + device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set. + * - ``V4L2_FMT_FLAG_CSC_YCBCR_ENC`` + - 0x0080 + - The driver allows the application to try to change the default + Y'CbCr encoding. This flag is relevant only for capture devices. + The application can ask to configure the Y'CbCr encoding of the capture device + when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set. + * - ``V4L2_FMT_FLAG_CSC_HSV_ENC`` + - 0x0080 + - The driver allows the application to try to change the default + HSV encoding. This flag is relevant only for capture devices. + The application can ask to configure the HSV encoding of the capture device + when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set. + * - ``V4L2_FMT_FLAG_CSC_QUANTIZATION`` + - 0x0100 + - The driver allows the application to try to change the default + quantization. This flag is relevant only for capture devices. + The application can ask to configure the quantization of the capture + device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with + :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set. Return Value ============ |