Re: [PATCH v12 11/17] media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS control

["Jernej Škrabec" <jernej.skrabec@gmail.com>]

Hi Benjamin!

Dne petek, 08. julij 2022 ob 14:05:48 CEST je Benjamin Gaignard napisal(a):
> The number of 'entry point offset' can be very variable.
> Instead of using a large static array define a v4l2 dynamic array
> of U32 (V4L2_CTRL_TYPE_U32).
> The number of entry point offsets is reported by the elems field
> and in struct v4l2_ctrl_hevc_slice_params.num_entry_point_offsets
> field.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
> ---
> version 12:
> - Reword num_entry_point_offsets documentation
> 
>  .../userspace-api/media/v4l/ext-ctrls-codec.rst     | 13 +++++++++++++
>  drivers/media/v4l2-core/v4l2-ctrls-defs.c           |  5 +++++
>  include/media/hevc-ctrls.h                          |  5 ++++-
>  3 files changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index
> c2e0adece613..0cd967126fdf 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -3010,6 +3010,11 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
>      * - __u32
>        - ``data_bit_offset``
>        - Offset (in bits) to the video data in the current slice data.
> +    * - __u32
> +      - ``num_entry_point_offsets``
> +      - Specifies the number of entry point offset syntax elements in the
> slice header. +        When the driver supports it, the
> ``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS`` +        must be set.
>      * - __u8
>        - ``nal_unit_type``
>        - Specifies the coding type of the slice (B, P or I).
> @@ -3150,6 +3155,14 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> 
>      \normalsize
> 
> +``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
> +    Specifies entry point offsets in bytes.
> +    This control is a dynamically sized array. The number of entry point
> +    offsets is reported by the ``elems`` field.
> +    This bitstream parameter is defined according to :ref:`hevc`.
> +    They are described in section 7.4.7.1 "General slice segment header
> +    semantics" of the specification.

You forgot to update above description per Ezequiel comment.

Best regards,
Jernej

> +
>  ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
>      Specifies the HEVC scaling matrix parameters used for the scaling
> process for transform coefficients.
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> b/drivers/media/v4l2-core/v4l2-ctrls-defs.c index
> d594efbcbb93..e22921e7ea61 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1188,6 +1188,7 @@ const char *v4l2_ctrl_get_name(u32 id)
>  	case V4L2_CID_STATELESS_HEVC_DECODE_PARAMS:		return 
"HEVC Decode
> Parameters"; case V4L2_CID_STATELESS_HEVC_DECODE_MODE:		return 
"HEVC Decode
> Mode"; case V4L2_CID_STATELESS_HEVC_START_CODE:		return 
"HEVC Start Code";
> +	case V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS:	return 
"HEVC Entry
> Point Offsets";
> 
>  	/* Colorimetry controls */
>  	/* Keep the order of the 'case's the same as in v4l2-controls.h! 
*/
> @@ -1518,6 +1519,10 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum
> v4l2_ctrl_type *type, case V4L2_CID_STATELESS_HEVC_DECODE_PARAMS:
>  		*type = V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS;
>  		break;
> +	case V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS:
> +		*type = V4L2_CTRL_TYPE_U32;
> +		*flags |= V4L2_CTRL_FLAG_DYNAMIC_ARRAY;
> +		break;
>  	case V4L2_CID_STATELESS_VP9_COMPRESSED_HDR:
>  		*type = V4L2_CTRL_TYPE_VP9_COMPRESSED_HDR;
>  		break;
> diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> index a372c184689e..3a6601a46ced 100644
> --- a/include/media/hevc-ctrls.h
> +++ b/include/media/hevc-ctrls.h
> @@ -20,6 +20,7 @@
>  #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS	(V4L2_CID_CODEC_BASE 
+ 1012)
>  #define V4L2_CID_STATELESS_HEVC_DECODE_MODE	(V4L2_CID_CODEC_BASE + 1015)
>  #define V4L2_CID_STATELESS_HEVC_START_CODE	(V4L2_CID_CODEC_BASE + 1016)
> +#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (V4L2_CID_CODEC_BASE +
> 1017)
> 
>  /* enum v4l2_ctrl_type type values */
>  #define V4L2_CTRL_TYPE_HEVC_SPS 0x0120
> @@ -316,6 +317,8 @@ struct v4l2_hevc_pred_weight_table {
>   *
>   * @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 + * @num_entry_point_offsets: specifies the number of entry
> point offset syntax + *			     elements in the slice 
header.
>   * @nal_unit_type: specifies the coding type of the slice (B, P or I)
>   * @nuh_temporal_id_plus1: minus 1 specifies a temporal identifier for the
> NAL unit * @slice_type: see V4L2_HEVC_SLICE_TYPE_{}
> @@ -358,7 +361,7 @@ struct v4l2_hevc_pred_weight_table {
>  struct v4l2_ctrl_hevc_slice_params {
>  	__u32	bit_size;
>  	__u32	data_bit_offset;
> -
> +	__u32	num_entry_point_offsets;
>  	/* ISO/IEC 23008-2, ITU-T Rec. H.265: NAL unit header */
>  	__u8	nal_unit_type;
>  	__u8	nuh_temporal_id_plus1;