Re: [PATCH v5 09/17] media: uapi: HEVC: Define V4L2_CID_STATELESS_HEVC_SLICE_PARAMS as a dynamic array

[Benjamin Gaignard]

Le 08/04/2022 à 20:53, Nicolas Dufresne a écrit :
> Le jeudi 07 avril 2022 à 17:29 +0200, Benjamin Gaignard a écrit :
> > Make explicit that V4L2_CID_STATELESS_HEVC_SLICE_PARAMS control is
> > a dynamic array control type.
> > Some drivers may be able to receive multiple slices in one control
> > to improve decoding performance.
> >
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> > ---
> >   Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 2 ++
> >   include/media/hevc-ctrls.h                                | 3 +++
> >   2 files changed, 5 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > index 7fcc6c2bac4c..1aaf3b84b584 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -2964,6 +2964,8 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> >       These bitstream parameters are defined according to :ref:`hevc`.
> >       They are described in section 7.4.7 "General slice segment header
> >       semantics" of the specification.
> > +    This control is a dynamically sized 1-dimensional array,
> > +    V4L2_CTRL_FLAG_DYNAMIC_ARRAY flag must be set when using it.
> >   
> >   .. c:type:: v4l2_ctrl_hevc_slice_params
> >   
> > diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> > index 96a9b71d1def..28049e1a8a07 100644
> > --- a/include/media/hevc-ctrls.h
> > +++ b/include/media/hevc-ctrls.h
> > @@ -314,6 +314,9 @@ struct v4l2_hevc_pred_weight_table {
> >   /**
> >    * v4l2_ctrl_hevc_slice_params - HEVC slice parameters
> >    *
> > + * This control is a dynamically sized 1-dimensional array,
> > + * V4L2_CTRL_FLAG_DYNAMIC_ARRAY flag must be set when using it.
> > + *
> I'm not sure about this comment, but I'm sure you forgot:
>
>
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1505,6 +1505,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum
> v4l2_ctrl_type *type,
>                  break;
>          case V4L2_CID_STATELESS_HEVC_SLICE_PARAMS:
>                  *type = V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS;
> +               *flags |= V4L2_CTRL_FLAG_DYNAMIC_ARRAY;
>                  break;
>          case V4L2_CID_STATELESS_HEVC_SCALING_MATRIX:
>                  *type = V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX;
>
> Also, in AV1 we have V4L2_AV1_MAX_TILE_COUNT, which can be used in cfg.dims,
> something the driver will actually set. We could have
>
> #define V4L2_HEVC_MAX_TILE_COUNT 600
>
> And drives can set:
>
>     .dims = { V4L2_HEVC_MAX_TILE_COUNT },
>
> In the control config.

Ok that will be in v6

> >    * @bit_size: size (in bits) of the current slice data
> >    * @data_bit_offset: offset (in bits) to the video data in the current slice data
> >    * @nal_unit_type: specifies the coding type of the slice (B, P or I)