Re: [PATCH 03/10] media: uapi: h264: Split prediction weight parameters

[Ezequiel Garcia <ezequiel@collabora.com>]

On Thu, 2020-07-16 at 09:26 +0200, Hans Verkuil wrote:
> On 15/07/2020 22:22, Ezequiel Garcia wrote:
> > The prediction weight parameters are only required under
> > certain conditions, which depend on slice header parameters.
> > 
> > The slice header syntax specifies that the prediction
> > weight table is present if:
> > 
> > ((weighted_pred_flag && (slice_type == P || slice_type == SP)) || \
> > (weighted_bipred_idc == 1 && slice_type == B))
> > 
> > Given its size, it makes sense to move this table to its control,
> > so applications can avoid passing it if the slice doesn't specify it.
> > 
> > Before this change struct v4l2_ctrl_h264_slice_params was 960 bytes.
> > With this change, it's 188 bytes and struct v4l2_ctrl_h264_pred_weight
> > is 772 bytes.
> > 
> > Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> > ---
> >  .../userspace-api/media/v4l/ext-ctrls-codec.rst    | 14 +++++++++-----
> >  drivers/media/v4l2-core/v4l2-ctrls.c               |  6 ++++++
> >  drivers/staging/media/sunxi/cedrus/cedrus.h        |  1 +
> >  drivers/staging/media/sunxi/cedrus/cedrus_dec.c    |  2 ++
> >  drivers/staging/media/sunxi/cedrus/cedrus_h264.c   |  6 ++----
> >  include/media/h264-ctrls.h                         |  5 +++--
> >  6 files changed, 23 insertions(+), 11 deletions(-)
> > 
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > index 16bfc98ab2f6..d1695ae96700 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -1879,18 +1879,22 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
> >        - 0x00000008
> >        -
> >  
> > -``Prediction Weight Table``
> > -
> > -    The bitstream parameters are defined according to :ref:`h264`,
> > +``V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT (struct)``
> > +    Prediction weight table defined according to :ref:`h264`,
> >      section 7.4.3.2 "Prediction Weight Table Semantics". For further
> >      documentation, refer to the above specification, unless there is
> >      an explicit comment stating otherwise.
> >  
> > -.. c:type:: v4l2_h264_pred_weight_table
> > +    .. note::
> > +
> > +       This compound control is not yet part of the public kernel API and
> > +       it is expected to change.
> > +
> > +.. c:type:: v4l2_ctrl_h264_pred_weight
> >  
> >  .. cssclass:: longtable
> >  
> > -.. flat-table:: struct v4l2_h264_pred_weight_table
> > +.. flat-table:: struct v4l2_ctrl_h264_pred_weight
> >      :header-rows:  0
> >      :stub-columns: 0
> >      :widths:       1 1 2
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> > index 3f3fbcd60cc6..3a8a23e34c70 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> > @@ -1412,6 +1412,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> >  	case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:
> >  		*type = V4L2_CTRL_TYPE_H264_DECODE_PARAMS;
> >  		break;
> > +	case V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT:
> > +		*type = V4L2_CTRL_TYPE_H264_PRED_WEIGHT;
> > +		break;
> >  	case V4L2_CID_MPEG_VIDEO_VP8_FRAME_HEADER:
> >  		*type = V4L2_CTRL_TYPE_VP8_FRAME_HEADER;
> >  		break;
> > @@ -2553,6 +2556,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >  	case V4L2_CTRL_TYPE_H264_DECODE_PARAMS:
> >  		elem_size = sizeof(struct v4l2_ctrl_h264_decode_params);
> >  		break;
> > +	case V4L2_CTRL_TYPE_H264_PRED_WEIGHT:
> > +		elem_size = sizeof(struct v4l2_ctrl_h264_pred_weight);
> > +		break;
> >  	case V4L2_CTRL_TYPE_VP8_FRAME_HEADER:
> >  		elem_size = sizeof(struct v4l2_ctrl_vp8_frame_header);
> >  		break;
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.h b/drivers/staging/media/sunxi/cedrus/cedrus.h
> > index 96765555ab8a..80a0ecffa384 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus.h
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus.h
> > @@ -62,6 +62,7 @@ struct cedrus_h264_run {
> >  	const struct v4l2_ctrl_h264_scaling_matrix	*scaling_matrix;
> >  	const struct v4l2_ctrl_h264_slice_params	*slice_params;
> >  	const struct v4l2_ctrl_h264_sps			*sps;
> > +	const struct v4l2_ctrl_h264_pred_weight		*pred_weight;
> >  };
> >  
> >  struct cedrus_mpeg2_run {
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> > index 58c48e4fdfe9..047f773f64f9 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> > @@ -57,6 +57,8 @@ void cedrus_device_run(void *priv)
> >  			V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS);
> >  		run.h264.sps = cedrus_find_control_data(ctx,
> >  			V4L2_CID_MPEG_VIDEO_H264_SPS);
> > +		run.h264.pred_weight = cedrus_find_control_data(ctx,
> > +			V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT);
> >  		break;
> >  
> >  	case V4L2_PIX_FMT_HEVC_SLICE:
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > index cce527bbdf86..614b1b496e40 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > @@ -256,10 +256,8 @@ static void cedrus_write_scaling_lists(struct cedrus_ctx *ctx,
> >  static void cedrus_write_pred_weight_table(struct cedrus_ctx *ctx,
> >  					   struct cedrus_run *run)
> >  {
> > -	const struct v4l2_ctrl_h264_slice_params *slice =
> > -		run->h264.slice_params;
> > -	const struct v4l2_h264_pred_weight_table *pred_weight =
> > -		&slice->pred_weight_table;
> > +	const struct v4l2_ctrl_h264_pred_weight *pred_weight =
> > +		run->h264.pred_weight;
> >  	struct cedrus_dev *dev = ctx->dev;
> >  	int i, j, k;
> >  
> > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> > index bca4a9887e7e..da2ffb77b491 100644
> > --- a/include/media/h264-ctrls.h
> > +++ b/include/media/h264-ctrls.h
> > @@ -36,6 +36,7 @@
> >  #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS	(V4L2_CID_MPEG_BASE+1004)
> >  #define V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE	(V4L2_CID_MPEG_BASE+1005)
> >  #define V4L2_CID_MPEG_VIDEO_H264_START_CODE	(V4L2_CID_MPEG_BASE+1006)
> > +#define V4L2_CID_MPEG_VIDEO_H264_PRED_WEIGHT	(V4L2_CID_MPEG_BASE+1007)
> >  
> >  /* enum v4l2_ctrl_type type values */
> >  #define V4L2_CTRL_TYPE_H264_SPS			0x0110
> > @@ -43,6 +44,7 @@
> >  #define V4L2_CTRL_TYPE_H264_SCALING_MATRIX	0x0112
> >  #define V4L2_CTRL_TYPE_H264_SLICE_PARAMS	0x0113
> >  #define V4L2_CTRL_TYPE_H264_DECODE_PARAMS	0x0114
> > +#define V4L2_CTRL_TYPE_H264_PRED_WEIGHT		0x0115
> >  
> >  enum v4l2_mpeg_video_h264_decode_mode {
> >  	V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED,
> > @@ -125,7 +127,7 @@ struct v4l2_h264_weight_factors {
> >  	__s16 chroma_offset[32][2];
> >  };
> >  
> > -struct v4l2_h264_pred_weight_table {
> > +struct v4l2_ctrl_h264_pred_weight {
> >  	__u16 luma_log2_weight_denom;
> >  	__u16 chroma_log2_weight_denom;
> >  	struct v4l2_h264_weight_factors weight_factors[2];
> > @@ -174,7 +176,6 @@ struct v4l2_ctrl_h264_slice_params {
> >  	__s32 delta_pic_order_cnt0;
> >  	__s32 delta_pic_order_cnt1;
> >  
> > -	struct v4l2_h264_pred_weight_table pred_weight_table;
> >  	/* Size in bits of dec_ref_pic_marking() syntax element. */
> >  	__u32 dec_ref_pic_marking_bit_size;
> >  	/* Size in bits of pic order count syntax. */
> > 
> 
> Shouldn't this be added to union v4l2_ctrl_ptr as well?
> 

Yup, that's correct.

Thanks,
Ezequiel