Re: [PATCH v2 7/8] media: hevc: Add scaling matrix control

[Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>]

Le 14/06/2021 à 09:27, Hans Verkuil a écrit :
> On 10/06/2021 17:44, Benjamin Gaignard wrote:
> > HEVC scaling lists are used for the scaling process for transform
> > coefficients.
> > V4L2_HEVC_SPS_FLAG_SCALING_LIST_ENABLED has to set when they are
> > encoded in the bitstream.
> Comparing H264 with HEVC I noticed that the corresponding flag for H264 is
> called V4L2_H264_PPS_FLAG_SCALING_MATRIX_PRESENT.
>
> Should those names be aligned? Also, it is part of PPS for H264 and SPS in HEVC,
> is that difference correct?

In ITU specifications ("7.4.3.2.1 General sequence parameter set RBSP semantics") this flag is define like that:
scaling_list_enabled_flag equal to 1 specifies that a scaling list is used for the scaling process for transform coefficients.
scaling_list_enabled_flag equal to 0 specifies that scaling list is not used for the scaling process for transform coefficients.

So for me the naming is correct.

Regards,
Benjamin

> Regards,
>
> 	Hans
>
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> > ---
> > version 2:
> >   - Fix structure name in ext-ctrls-codec.rst
> >
> >   .../media/v4l/ext-ctrls-codec.rst             | 45 +++++++++++++++++++
> >   .../media/v4l/vidioc-queryctrl.rst            |  6 +++
> >   drivers/media/v4l2-core/v4l2-ctrls-core.c     |  6 +++
> >   drivers/media/v4l2-core/v4l2-ctrls-defs.c     |  4 ++
> >   include/media/hevc-ctrls.h                    | 11 +++++
> >   5 files changed, 72 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > index 8c6e2a11ed95..d4f40bb85263 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -3068,6 +3068,51 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> >   
> >       \normalsize
> >   
> > +``V4L2_CID_MPEG_VIDEO_HEVC_SCALING_MATRIX (struct)``
> > +    Specifies the HEVC scaling matrix parameters used for the scaling process
> > +    for transform coefficients.
> > +    These matrix and parameters are defined according to :ref:`hevc`.
> > +    They are described in section 7.4.5 "Scaling list data semantics" of
> > +    the specification.
> > +
> > +.. c:type:: v4l2_ctrl_hevc_scaling_matrix
> > +
> > +.. raw:: latex
> > +
> > +    \scriptsize
> > +
> > +.. tabularcolumns:: |p{5.4cm}|p{6.8cm}|p{5.1cm}|
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table:: struct v4l2_ctrl_hevc_scaling_matrix
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - __u8
> > +      - ``scaling_list_4x4[6][16]``
> > +      -
> > +    * - __u8
> > +      - ``scaling_list_8x8[6][64]``
> > +      -
> > +    * - __u8
> > +      - ``scaling_list_16x16[6][64]``
> > +      -
> > +    * - __u8
> > +      - ``scaling_list_32x32[2][64]``
> > +      -
> > +    * - __u8
> > +      - ``scaling_list_dc_coef_16x16[6]``
> > +      -
> > +    * - __u8
> > +      - ``scaling_list_dc_coef_32x32[2]``
> > +      -
> > +
> > +.. raw:: latex
> > +
> > +    \normalsize
> > +
> >   .. c:type:: v4l2_hevc_dpb_entry
> >   
> >   .. raw:: latex
> > diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> > index f9ecf6276129..2f491c17dd5d 100644
> > --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> > +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> > @@ -495,6 +495,12 @@ See also the examples in :ref:`control`.
> >         - n/a
> >         - A struct :c:type:`v4l2_ctrl_hevc_slice_params`, containing HEVC
> >   	slice parameters for stateless video decoders.
> > +    * - ``V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX``
> > +      - n/a
> > +      - n/a
> > +      - n/a
> > +      - A struct :c:type:`v4l2_ctrl_hevc_scaling_matrix`, containing HEVC
> > +	scaling matrix for stateless video decoders.
> >       * - ``V4L2_CTRL_TYPE_VP8_FRAME``
> >         - n/a
> >         - n/a
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > index c4b5082849b6..70adfc1b9c81 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > @@ -687,6 +687,9 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> >   
> >   		break;
> >   
> > +	case V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX:
> > +		break;
> > +
> >   	case V4L2_CTRL_TYPE_AREA:
> >   		area = p;
> >   		if (!area->width || !area->height)
> > @@ -1240,6 +1243,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >   	case V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS:
> >   		elem_size = sizeof(struct v4l2_ctrl_hevc_slice_params);
> >   		break;
> > +	case V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX:
> > +		elem_size = sizeof(struct v4l2_ctrl_hevc_scaling_matrix);
> > +		break;
> >   	case V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS:
> >   		elem_size = sizeof(struct v4l2_ctrl_hevc_decode_params);
> >   		break;
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > index b6344bbf1e00..cb29c2a7fabe 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> > @@ -996,6 +996,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_SPS:			return "HEVC Sequence Parameter Set";
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_PPS:			return "HEVC Picture Parameter Set";
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS:		return "HEVC Slice Parameters";
> > +	case V4L2_CID_MPEG_VIDEO_HEVC_SCALING_MATRIX:		return "HEVC Scaling Matrix";
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_DECODE_PARAMS:		return "HEVC Decode Parameters";
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_DECODE_MODE:		return "HEVC Decode Mode";
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_START_CODE:		return "HEVC Start Code";
> > @@ -1488,6 +1489,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS:
> >   		*type = V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS;
> >   		break;
> > +	case V4L2_CID_MPEG_VIDEO_HEVC_SCALING_MATRIX:
> > +		*type = V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX;
> > +		break;
> >   	case V4L2_CID_MPEG_VIDEO_HEVC_DECODE_PARAMS:
> >   		*type = V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS;
> >   		break;
> > diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> > index 53c0038c792b..0e5c4a2eecff 100644
> > --- a/include/media/hevc-ctrls.h
> > +++ b/include/media/hevc-ctrls.h
> > @@ -19,6 +19,7 @@
> >   #define V4L2_CID_MPEG_VIDEO_HEVC_SPS		(V4L2_CID_CODEC_BASE + 1008)
> >   #define V4L2_CID_MPEG_VIDEO_HEVC_PPS		(V4L2_CID_CODEC_BASE + 1009)
> >   #define V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS	(V4L2_CID_CODEC_BASE + 1010)
> > +#define V4L2_CID_MPEG_VIDEO_HEVC_SCALING_MATRIX	(V4L2_CID_CODEC_BASE + 1011)
> >   #define V4L2_CID_MPEG_VIDEO_HEVC_DECODE_PARAMS	(V4L2_CID_CODEC_BASE + 1012)
> >   #define V4L2_CID_MPEG_VIDEO_HEVC_DECODE_MODE	(V4L2_CID_CODEC_BASE + 1015)
> >   #define V4L2_CID_MPEG_VIDEO_HEVC_START_CODE	(V4L2_CID_CODEC_BASE + 1016)
> > @@ -27,6 +28,7 @@
> >   #define V4L2_CTRL_TYPE_HEVC_SPS 0x0120
> >   #define V4L2_CTRL_TYPE_HEVC_PPS 0x0121
> >   #define V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS 0x0122
> > +#define V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX 0x0123
> >   #define V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS 0x0124
> >   
> >   enum v4l2_mpeg_video_hevc_decode_mode {
> > @@ -224,6 +226,15 @@ struct v4l2_ctrl_hevc_decode_params {
> >   	__u64	flags;
> >   };
> >   
> > +struct v4l2_ctrl_hevc_scaling_matrix {
> > +	__u8	scaling_list_4x4[6][16];
> > +	__u8	scaling_list_8x8[6][64];
> > +	__u8	scaling_list_16x16[6][64];
> > +	__u8	scaling_list_32x32[2][64];
> > +	__u8	scaling_list_dc_coef_16x16[6];
> > +	__u8	scaling_list_dc_coef_32x32[2];
> > +};
> > +
> >   /*  MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */
> >   #define V4L2_CID_CODEC_HANTRO_BASE				(V4L2_CTRL_CLASS_CODEC | 0x1200)
> >   /*