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Subject: Re: [PATCH v2 7/8] media: hevc: Add scaling matrix control
To:     Hans Verkuil <hverkuil@xs4all.nl>, ezequiel@collabora.com,
        p.zabel@pengutronix.de, mchehab@kernel.org, shawnguo@kernel.org,
        s.hauer@pengutronix.de, festevam@gmail.com,
        gregkh@linuxfoundation.org, mripard@kernel.org,
        paul.kocialkowski@bootlin.com, wens@csie.org,
        jernej.skrabec@siol.net, emil.l.velikov@gmail.com,
        andrzej.p@collabora.com, jc@kynesim.co.uk, jernej.skrabec@gmail.com
Cc:     kernel@pengutronix.de, linux-imx@nxp.com,
        linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20210610154442.806107-1-benjamin.gaignard@collabora.com>
 <20210610154442.806107-8-benjamin.gaignard@collabora.com>
 <87a1e585-688e-7c4d-b9a9-24f42772a1a8@xs4all.nl>
From:   Benjamin Gaignard <benjamin.gaignard@collabora.com>
Message-ID: <d5b010c8-c0c5-8800-b2c3-9371923ca10c@collabora.com>
Date:   Mon, 14 Jun 2021 09:43:00 +0200
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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@collabora.com>
>> ---
>> 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)
>>   /*
>>