RE: [Patch v3 05/15] Documention: v4l: Documentation for VP9 CIDs.

["Aakarsh Jain" <aakarsh.jain@samsung.com>]

> -----Original Message-----
> From: Hans Verkuil [mailto:hverkuil-cisco@xs4all.nl]
> Sent: 24 November 2022 16:54
> To: aakarsh jain <aakarsh.jain@samsung.com>; linux-arm-
> kernel@lists.infradead.org; linux-media@vger.kernel.org; linux-
> kernel@vger.kernel.org; devicetree@vger.kernel.org
> Cc: m.szyprowski@samsung.com; andrzej.hajda@intel.com;
> mchehab@kernel.org; ezequiel@vanguardiasur.com.ar;
> jernej.skrabec@gmail.com; benjamin.gaignard@collabora.com;
> stanimir.varbanov@linaro.org; dillon.minfei@gmail.com;
> david.plowman@raspberrypi.com; mark.rutland@arm.com;
> robh+dt@kernel.org; krzk+dt@kernel.org; andi@etezian.org;
> alim.akhtar@samsung.com; aswani.reddy@samsung.com;
> pankaj.dubey@samsung.com; linux-fsd@tesla.com; smitha.t@samsung.com
> Subject: Re: [Patch v3 05/15] Documention: v4l: Documentation for VP9 CIDs.
> 
> On 11/10/2022 14:25, aakarsh jain wrote:
> > From: Smitha T Murthy <smitha.t@samsung.com>
> >
> > Adds V4l2 controls for VP9 encoder documention.
> >
> > Cc: linux-fsd@tesla.com
> > Signed-off-by: Smitha T Murthy <smitha.t@samsung.com>
> > Signed-off-by: Aakarsh Jain <aakarsh.jain@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 2a165ae063fb..2277d83a7cf0 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -2187,6 +2187,16 @@ enum v4l2_mpeg_video_vp8_profile -
> >      * - ``V4L2_MPEG_VIDEO_VP8_PROFILE_3``
> >        - Profile 3
> >
> > +VP9 Control Reference
> 
> This is wrong. There is a VPX Control Reference section for both VP8 and VP9
> controls. That's where this should be added. I suspect several of the controls
> you are adding here already exist, e.g.
> V4L2_CID_MPEG_VIDEO_VPX_MIN_QP. The documentation may have to be
> updated to specify that it is for both VP8 and VP9.
> 
okay. I will add all VP9 Control IDs in VPX Control reference section.
> > +---------------------
> > +
> > +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``
> > @@ -2253,6 +2263,163 @@ enum v4l2_mpeg_video_vp9_level -
> >      * - ``V4L2_MPEG_VIDEO_VP9_LEVEL_6_2``
> >        - Level 6.2
> >
> > +``V4L2_CID_CODEC_VP9_I_FRAME_QP``
> 
> If you do need to add new controls, then please use the same
> MPEG_VIDEO_ prefix.
> It's a bit ugly and historical, but let's keep it consistent with the others.
> 
But initially you recommended to use CODEC instead of MPEG_VIDEO.
https://patchwork.kernel.org/project/linux-media/patch/20220517125548.14746-7-smitha.t@samsung.com/

Anyway I will rename from CODEC to MPEG_VIDEO again.

> Regards,
> 
> 	Hans
> 
> > +    Quantization parameter for an I frame for VP9. Valid range: from 1 to
> 255.
> > +
> > +``V4L2_CID_CODEC_VP9_P_FRAME_QP``
> > +    Quantization parameter for an P frame for VP9. Valid range: from 1 to
> 255.
> > +
> > +``V4L2_CID_CODEC_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_CODEC_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_CODEC_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_CODEC_VP9_GF_REFRESH_PERIOD``
> > +    Indicates the refresh period of the golden frame for VP9 encoder.
> > +
> > +.. _v4l2-vp9-golden-frame-sel:
> > +
> > +``V4L2_CID_CODEC_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_CODEC_VP9_GOLDEN_FRAME_USE_PREV``
> > +      - Use the (n-2)th frame as a golden frame, current frame index being
> > +        'n'.
> > +    * - ``V4L2_CID_CODEC_VP9_GOLDEN_FRAME_USE_REF_PERIOD``
> > +      - Use the previous specific frame indicated by
> > +        ``V4L2_CID_CODEC_VP9_GF_REFRESH_PERIOD`` as a
> > +        golden frame.
> > +
> > +.. raw:: latex
> > +
> > +    \normalsize
> > +
> > +
> > +``V4L2_CID_CODEC_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_CODEC_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_CODEC_VP9_1_REF_PFRAME``
> > +      - Indicates one reference frame, last encoded frame will be searched.
> > +    * - ``V4L2_CID_CODEC_VP9_GOLDEN_FRAME_USE_REF_PERIOD``
> > +      - Indicates 2 reference frames, last encoded frame and golden frame
> > +        will be searched.
> > +
> > +.. raw:: latex
> > +
> > +    \normalsize
> > +
> > +
> > +``V4L2_CID_CODEC_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_CODEC_VP9_HIERARCHY_RC_ENABLE``
> > +    Indicates enabling of bit rate for hierarchical coding layers VP9 encoder.
> > +
> > +``V4L2_CID_CODEC_VP9_HIER_CODING_L0_BR``
> > +    Indicates bit rate for hierarchical coding layer 0 for VP9 encoder.
> > +
> > +``V4L2_CID_CODEC_VP9_HIER_CODING_L1_BR``
> > +    Indicates bit rate for hierarchical coding layer 1 for VP9 encoder.
> > +
> > +``V4L2_CID_CODEC_VP9_HIER_CODING_L2_BR``
> > +    Indicates bit rate for hierarchical coding layer 2 for VP9 encoder.
> > +
> > +``V4L2_CID_CODEC_VP9_HIER_CODING_L0_QP``
> > +    Indicates quantization parameter for hierarchical coding layer 0.
> > +    Valid range: [V4L2_CID_CODEC_VP9_MIN_QP,
> > +    V4L2_CID_CODEC_VP9_MAX_QP].
> > +
> > +``V4L2_CID_CODEC_VP9_HIER_CODING_L1_QP``
> > +    Indicates quantization parameter for hierarchical coding layer 1.
> > +    Valid range: [V4L2_CID_CODEC_VP9_MIN_QP,
> > +    V4L2_CID_CODEC_VP9_MAX_QP].
> > +
> > +``V4L2_CID_CODEC_VP9_HIER_CODING_L2_QP``
> > +    Indicates quantization parameter for hierarchical coding layer 2.
> > +    Valid range: [V4L2_CID_CODEC_VP9_MIN_QP,
> > +    V4L2_CID_CODEC_VP9_MAX_QP].
> > +
> > +.. _v4l2-vp9-max-partition-depth:
> > +
> > +``V4L2_CID_CODEC_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_CODEC_VP9_0_PARTITION``
> > +      - No coding unit partition depth.
> > +    * - ``V4L2_CID_CODEC_VP9_1_PARTITION``
> > +      - Allows one coding unit partition depth.
> > +
> > +.. raw:: latex
> > +
> > +    \normalsize
> > +
> > +
> > +``V4L2_CID_CODEC_VP9_DISABLE_INTRA_PU_SPLIT``
> > +    Zero indicates enable intra NxN PU split.
> > +    One indicates disable intra NxN PU split.
> > +
> > +``V4L2_CID_CODEC_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
> >
> ==========================================================
> =
Thanks for the review.