[PATCH v6 09/17] media: uapi: HEVC: Define V4L2_CID_STATELESS_HEVC_SLICE_PARAMS as a dynamic array

[Jernej Škrabec]

Dne petek, 27. maj 2022 ob 16:31:26 CEST je Benjamin Gaignard napisal(a):
> 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.
> 
> Define the max size of the dynamic that can driver can set in .dims = {}.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard at collabora.com>
> ---
> version 6:
> - Set V4L2_CTRL_FLAG_DYNAMIC_ARRAY flag automatically when using
>   V4L2_CID_STATELESS_HEVC_SLICE_PARAMS control.
> - Add a define for max slices count
> 
>  Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 2 ++
>  drivers/media/v4l2-core/v4l2-ctrls-defs.c                 | 1 +
>  include/media/hevc-ctrls.h                                | 5 +++++
>  3 files changed, 8 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/
Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index 06b967de140c..0796b1563daa 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -2986,6 +2986,8 @@ 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/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-
core/v4l2-ctrls-defs.c
> index 9f55503cd3d6..d594efbcbb93 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1510,6 +1510,7 @@ 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;

This change breaks Cedrus. I'll check what needs to be changed.

Best regards,
Jernej

>  		break;
>  	case V4L2_CID_STATELESS_HEVC_SCALING_MATRIX:
>  		*type = V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX;
> diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> index 0dbd5d681c28..140151609c96 100644
> --- a/include/media/hevc-ctrls.h
> +++ b/include/media/hevc-ctrls.h
> @@ -311,9 +311,14 @@ struct v4l2_hevc_pred_weight_table {
>  #define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_LOOP_FILTER_ACROSS_SLICES_ENABLED 
(1ULL << 8)
>  #define V4L2_HEVC_SLICE_PARAMS_FLAG_DEPENDENT_SLICE_SEGMENT	(1ULL << 
9)
>  
> +#define V4L2_HEVC_SLICE_MAX_COUNT	600
> +
>  /**
>   * 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.
> + *
>   * @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)
> -- 
> 2.32.0
> 
>