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Diffstat (limited to 'Documentation/media/uapi/v4l/pixfmt-compressed.rst')
| -rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-compressed.rst | 67 |
1 files changed, 57 insertions, 10 deletions
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst index 4b701fc7653e..292fdc116c77 100644 --- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst +++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst @@ -41,7 +41,12 @@ Compressed Formats - ``V4L2_PIX_FMT_H264`` - 'H264' - - H264 video elementary stream with start codes. + - H264 Access Unit. + The decoder expects one Access Unit per buffer. + The encoder generates one Access Unit per buffer. + If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM`` + then the decoder has no requirements since it can parse all the + information from the raw bytestream. * .. _V4L2-PIX-FMT-H264-NO-SC: - ``V4L2_PIX_FMT_H264_NO_SC`` @@ -52,16 +57,19 @@ Compressed Formats - ``V4L2_PIX_FMT_H264_MVC`` - 'M264' - H264 MVC video elementary stream. - * .. _V4L2-PIX-FMT-H264-SLICE-RAW: + * .. _V4L2-PIX-FMT-H264-SLICE: - - ``V4L2_PIX_FMT_H264_SLICE_RAW`` + - ``V4L2_PIX_FMT_H264_SLICE`` - 'S264' - H264 parsed slice data, without the start code and as extracted from the H264 bitstream. This format is adapted for stateless video decoders that implement an H264 pipeline (using the :ref:`mem2mem` and :ref:`media-request-api`). - Metadata associated with the frame to decode are required to - be passed through the ``V4L2_CID_MPEG_VIDEO_H264_SPS``, + This pixelformat has two modifiers that must be set at least once + through the ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE`` + and ``V4L2_CID_MPEG_VIDEO_H264_START_CODE`` controls. + In addition, metadata associated with the frame to decode are + required to be passed through the ``V4L2_CID_MPEG_VIDEO_H264_SPS``, ``V4L2_CID_MPEG_VIDEO_H264_PPS``, ``V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX``, ``V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS`` and @@ -86,12 +94,20 @@ Compressed Formats - ``V4L2_PIX_FMT_MPEG1`` - 'MPG1' - - MPEG1 video elementary stream. + - MPEG1 Picture. Each buffer starts with a Picture header, followed + by other headers as needed and ending with the Picture data. + If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM`` + then the decoder has no requirements since it can parse all the + information from the raw bytestream. * .. _V4L2-PIX-FMT-MPEG2: - ``V4L2_PIX_FMT_MPEG2`` - 'MPG2' - - MPEG2 video elementary stream. + - MPEG2 Picture. Each buffer starts with a Picture header, followed + by other headers as needed and ending with the Picture data. + If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM`` + then the decoder has no requirements since it can parse all the + information from the raw bytestream. * .. _V4L2-PIX-FMT-MPEG2-SLICE: - ``V4L2_PIX_FMT_MPEG2_SLICE`` @@ -132,17 +148,46 @@ Compressed Formats - ``V4L2_PIX_FMT_VP8`` - 'VP80' - - VP8 video elementary stream. + - VP8 compressed video frame. The encoder generates one + compressed frame per buffer, and the decoder requires one + compressed frame per buffer. + * .. _V4L2-PIX-FMT-VP8-FRAME: + + - ``V4L2_PIX_FMT_VP8_FRAME`` + - 'VP8F' + - VP8 parsed frame, as extracted from the container. + This format is adapted for stateless video decoders that implement a + VP8 pipeline (using the :ref:`mem2mem` and :ref:`media-request-api`). + Metadata associated with the frame to decode is required to be passed + through the ``V4L2_CID_MPEG_VIDEO_VP8_FRAME_HEADER`` control. + See the :ref:`associated Codec Control IDs <v4l2-mpeg-vp8>`. + Exactly one output and one capture buffer must be provided for use with + this pixel format. The output buffer must contain the appropriate number + of macroblocks to decode a full corresponding frame to the matching + capture buffer. + + .. note:: + + This format is not yet part of the public kernel API and it + is expected to change. + * .. _V4L2-PIX-FMT-VP9: - ``V4L2_PIX_FMT_VP9`` - 'VP90' - - VP9 video elementary stream. + - VP9 compressed video frame. The encoder generates one + compressed frame per buffer, and the decoder requires one + compressed frame per buffer. * .. _V4L2-PIX-FMT-HEVC: - ``V4L2_PIX_FMT_HEVC`` - 'HEVC' - - HEVC/H.265 video elementary stream. + - HEVC/H.265 Access Unit. + The decoder expects one Access Unit per buffer. + The encoder generates one Access Unit per buffer. + If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM`` + then the decoder has no requirements since it can parse all the + information from the raw bytestream. * .. _V4L2-PIX-FMT-FWHT: - ``V4L2_PIX_FMT_FWHT`` @@ -150,6 +195,8 @@ Compressed Formats - Video elementary stream using a codec based on the Fast Walsh Hadamard Transform. This codec is implemented by the vicodec ('Virtual Codec') driver. See the codec-fwht.h header for more details. + :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM`` + since the decoder can parse all the information from the raw bytestream. * .. _V4L2-PIX-FMT-FWHT-STATELESS: - ``V4L2_PIX_FMT_FWHT_STATELESS`` |