Re: [PATCH 06/20] Documention: v4l: Documentation for VP9 CIDs.

Hans Verkuil
2022-05-18T09:46:32Z

Hi Smitha,

On 5/17/22 14:55, Smitha T Murthy wrote:
> Adds V4l2 controls for VP9 encoder documention.
>
> Cc: linux-fsd@tesla.com
> Signed-off-by: Smitha T Murthy <smitha.t@samsung.com>
> ---
> .../media/v4l/ext-ctrls-codec.rst | 167 ++++++++++++++++++
> 1 file changed, 167 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index 4cd7c541fc30..1b617a08f973 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -2165,6 +2165,16 @@ enum v4l2_mpeg_video_vp8_profile -
> * - ``V4L2_MPEG_VIDEO_VP8_PROFILE_3``
> - Profile 3
>
> +VP9 Control Reference
> +---------------------
> +
> +The VP9 controls include controls for encoding parameters of VP9 video
> +codec.
> +
> +.. _vp9-control-id:
> +
> +VP9 Control IDs
> +
> .. _v4l2-mpeg-video-vp9-profile:
>
> ``V4L2_CID_MPEG_VIDEO_VP9_PROFILE``
> @@ -2231,6 +2241,163 @@ enum v4l2_mpeg_video_vp9_level -
> * - ``V4L2_MPEG_VIDEO_VP9_LEVEL_6_2``
> - Level 6.2
>
> +``V4L2_CID_MPEG_VIDEO_VP9_I_FRAME_QP``
> + Quantization parameter for an I frame for VP9. Valid range: from 1 to 255.

Hmm, for this CID and most of the others you added there already exists a CID:
V4L2_CID_MPEG_VIDEO_VPX_I_FRAME_QP.

It's called VPX since it is valid for both VP8 and VP9.

So I think quite a few of these VP9 controls can be dropped, unless I am missing
something?

Regards,

Hans

> +
> +``V4L2_CID_MPEG_VIDEO_VP9_P_FRAME_QP``
> + Quantization parameter for an P frame for VP9. Valid range: from 1 to 255.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_MAX_QP``
> + Maximum quantization parameter for VP9. Valid range: from 1 to 255.
> + Recommended range for MFC is from 230 to 255.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_MIN_QP``
> + Minimum quantization parameter for VP9. Valid range: from 1 to 255.
> + Recommended range for MFC is from 1 to 24.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_RC_FRAME_RATE``
> + Indicates the number of evenly spaced subintervals, called ticks, within
> + one second. This is a 16 bit unsigned integer and has a maximum value up to
> + 0xffff and a minimum value of 1.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_GF_REFRESH_PERIOD``
> + Indicates the refresh period of the golden frame for VP9 encoder.
> +
> +.. _v4l2-vp9-golden-frame-sel:
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_GOLDEN_FRAMESEL``
> + (enum)
> +
> +enum v4l2_mpeg_vp9_golden_framesel -
> + Selects the golden frame for encoding. Valid when NUM_OF_REF is 2.
> + Possible values are:
> +
> +.. raw:: latex
> +
> + \footnotesize
> +
> +.. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> +
> + * - ``V4L2_CID_MPEG_VIDEO_VP9_GOLDEN_FRAME_USE_PREV``
> + - Use the (n-2)th frame as a golden frame, current frame index being
> + 'n'.
> + * - ``V4L2_CID_MPEG_VIDEO_VP9_GOLDEN_FRAME_USE_REF_PERIOD``
> + - Use the previous specific frame indicated by
> + ``V4L2_CID_MPEG_VIDEO_VP9_GF_REFRESH_PERIOD`` as a
> + golden frame.
> +
> +.. raw:: latex
> +
> + \normalsize
> +
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIERARCHY_QP_ENABLE``
> + Allows host to specify the quantization parameter values for each
> + temporal layer through HIERARCHICAL_QP_LAYER. This is valid only
> + if HIERARCHICAL_CODING_LAYER is greater than 1. Setting the control
> + value to 1 enables setting of the QP values for the layers.
> +
> +.. _v4l2-vp9-ref-number-of-pframes:
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_REF_NUMBER_FOR_PFRAMES``
> + (enum)
> +
> +enum v4l2_mpeg_vp9_ref_num_for_pframes -
> + Number of reference pictures for encoding P frames.
> +
> +.. raw:: latex
> +
> + \footnotesize
> +
> +.. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> +
> + * - ``V4L2_CID_MPEG_VIDEO_VP9_1_REF_PFRAME``
> + - Indicates one reference frame, last encoded frame will be searched.
> + * - ``V4L2_CID_MPEG_VIDEO_VP9_GOLDEN_FRAME_USE_REF_PERIOD``
> + - Indicates 2 reference frames, last encoded frame and golden frame
> + will be searched.
> +
> +.. raw:: latex
> +
> + \normalsize
> +
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIERARCHICAL_CODING_LAYER``
> + Indicates the number of hierarchial coding layer.
> + In normal encoding (non-hierarchial coding), it should be zero.
> + VP9 has upto 3 layer of encoder.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIERARCHY_RC_ENABLE``
> + Indicates enabling of bit rate for hierarchical coding layers VP9 encoder.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIER_CODING_L0_BR``
> + Indicates bit rate for hierarchical coding layer 0 for VP9 encoder.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIER_CODING_L1_BR``
> + Indicates bit rate for hierarchical coding layer 1 for VP9 encoder.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIER_CODING_L2_BR``
> + Indicates bit rate for hierarchical coding layer 2 for VP9 encoder.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIER_CODING_L0_QP``
> + Indicates quantization parameter for hierarchical coding layer 0.
> + Valid range: [V4L2_CID_MPEG_VIDEO_VP9_MIN_QP,
> + V4L2_CID_MPEG_VIDEO_VP9_MAX_QP].
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIER_CODING_L1_QP``
> + Indicates quantization parameter for hierarchical coding layer 1.
> + Valid range: [V4L2_CID_MPEG_VIDEO_VP9_MIN_QP,
> + V4L2_CID_MPEG_VIDEO_VP9_MAX_QP].
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_HIER_CODING_L2_QP``
> + Indicates quantization parameter for hierarchical coding layer 2.
> + Valid range: [V4L2_CID_MPEG_VIDEO_VP9_MIN_QP,
> + V4L2_CID_MPEG_VIDEO_VP9_MAX_QP].
> +
> +.. _v4l2-vp9-max-partition-depth:
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_MAX_PARTITION_DEPTH``
> + (enum)
> +
> +enum v4l2_mpeg_vp9_num_partitions -
> + Indicate maximum coding unit depth.
> +
> +.. raw:: latex
> +
> + \footnotesize
> +
> +.. tabularcolumns:: |p{9.0cm}|p{8.0cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> +
> + * - ``V4L2_CID_MPEG_VIDEO_VP9_0_PARTITION``
> + - No coding unit partition depth.
> + * - ``V4L2_CID_MPEG_VIDEO_VP9_1_PARTITION``
> + - Allows one coding unit partition depth.
> +
> +.. raw:: latex
> +
> + \normalsize
> +
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_DISABLE_INTRA_PU_SPLIT``
> + Zero indicates enable intra NxN PU split.
> + One indicates disable intra NxN PU split.
> +
> +``V4L2_CID_MPEG_VIDEO_VP9_DISABLE_IVF_HEADER``
> + Indicates IVF header generation. Zero indicates enable IVF format.
> + One indicates disable IVF format.
> +
>
> High Efficiency Video Coding (HEVC/H.265) Control Reference
> ===========================================================