diff options
Diffstat (limited to 'Documentation/media')
| -rw-r--r-- | Documentation/media/uapi/v4l/ext-ctrls-codec.rst | 57 | ||||
| -rw-r--r-- | Documentation/media/uapi/v4l/pixfmt-compressed.rst | 6 |
2 files changed, 60 insertions, 3 deletions
diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst index c5f39dd50043..1da17a2c94d7 100644 --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst @@ -1748,6 +1748,14 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - - ``size`` - * - __u32 + - ``start_byte_offset`` + Offset (in bytes) from the beginning of the OUTPUT buffer to the start + of the slice. If the slice starts with a start code, then this is the + offset to such start code. When operating in slice-based decoding mode + (see :c:type:`v4l2_mpeg_video_h264_decode_mode`), this field should + be set to 0. When operating in frame-based decoding mode, this field + should be 0 for the first slice. + * - __u32 - ``header_bit_size`` - * - __u16 @@ -1930,7 +1938,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - - * - __u16 - ``num_slices`` - - Number of slices needed to decode the current frame + - Number of slices needed to decode the current frame/field. When + operating in slice-based decoding mode (see + :c:type:`v4l2_mpeg_video_h264_decode_mode`), this field + should always be set to one. * - __u16 - ``nal_ref_idc`` - NAL reference ID value coming from the NAL Unit header @@ -2021,6 +2032,50 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - - 0x00000004 - The DPB entry is a long term reference frame +``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE (enum)`` + Specifies the decoding mode to use. Currently exposes slice-based and + frame-based decoding but new modes might be added later on. + This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE + pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE + are required to set this control in order to specify the decoding mode + that is expected for the buffer. + Drivers may expose a single or multiple decoding modes, depending + on what they can support. + + .. note:: + + This menu control is not yet part of the public kernel API and + it is expected to change. + +.. c:type:: v4l2_mpeg_video_h264_decode_mode + +.. cssclass:: longtable + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - ``V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED`` + - 0 + - Decoding is done at the slice granularity. + In this mode, ``num_slices`` field in struct + :c:type:`v4l2_ctrl_h264_decode_params` should be set to 1, + and ``start_byte_offset`` in struct + :c:type:`v4l2_ctrl_h264_slice_params` should be set to 0. + The OUTPUT buffer must contain a single slice. + * - ``V4L2_MPEG_VIDEO_H264_DECODE_MODE_FRAME_BASED`` + - 1 + - Decoding is done at the frame granularity. + In this mode, ``num_slices`` field in struct + :c:type:`v4l2_ctrl_h264_decode_params` should be set to the number + of slices in the frame, and ``start_byte_offset`` in struct + :c:type:`v4l2_ctrl_h264_slice_params` should be set accordingly + for each slice. For the first slice, ``start_byte_offset`` should + be zero. + The OUTPUT buffer must contain all slices needed to decode the + frame. The OUTPUT buffer must also contain both fields. + .. _v4l2-mpeg-mpeg2: ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)`` diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst index 9b65473a2288..d666eb51741a 100644 --- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst +++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst @@ -60,8 +60,10 @@ Compressed Formats 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 a modifier that must be set at least once + through the ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE`` control. + 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 |