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Message-ID: <b5f4e1cc04ba35d92839932d431726fd42f24320.camel@ndufresne.ca>
Subject: Re: [PATCH V2] [media] v4l2: Add AV1 pixel format
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Shi Hao <hao.shi@amlogic.com>, laurent.pinchart@ideasonboard.com,
        nanxin.qin@amlogic.com
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        mchehab@kernel.org, hans.verkuil@cisco.com,
        hverkuil-cisco@xs4all.nl, ezequiel@vanguardiasur.com.ar,
        sakari.ailus@linux.intel.com, ribalda@chromium.org,
        stanimir.varbanov@linaro.org, hui.zhang@amlogic.com,
        lele.xiang@amlogic.com
Date:   Mon, 12 Sep 2022 16:45:22 +0100
In-Reply-To: <20220830014032.1245359-1-hao.shi@amlogic.com>
References: <20220830014032.1245359-1-hao.shi@amlogic.com>
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Hi Shi,

thanks for the patches, check inline for some comments. Generally speaking,=
 we
don't usually add formats ahead of time unless we have a good rationale to =
do
so. Should be expect a companion series against the amlogic decoder driver =
that
enables this ?

Le mardi 30 ao=C3=BBt 2022 =C3=A0 09:40 +0800, Shi Hao a =C3=A9crit=C2=A0:
> From: "hao.shi" <hao.shi@amlogic.com>
>=20
> Add AV1 compressed pixel format. It is the more common format.
>=20
> Signed-off-by: Hao Shi <hao.shi@amlogic.com>
> ---
>  .../userspace-api/media/v4l/pixfmt-compressed.rst        | 9 +++++++++
>  drivers/media/v4l2-core/v4l2-ioctl.c                     | 1 +
>  include/uapi/linux/videodev2.h                           | 1 +
>  3 files changed, 11 insertions(+)
>=20
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst =
b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
> index 506dd3c98884..5bdeeebdf9f5 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
> @@ -232,6 +232,15 @@ Compressed Formats
>          Metadata associated with the frame to decode is required to be p=
assed
>          through the ``V4L2_CID_STATELESS_FWHT_PARAMS`` control.
>  	See the :ref:`associated Codec Control ID <codec-stateless-fwht>`.
> +    * .. _V4L2-PIX-FMT-AV1:
> +
> +      - ``V4L2_PIX_FMT_AV1``
> +      - 'AV1'
> +      - AV1 Access Unit. The decoder expects one Access Unit per buffer.

I believe this is using a MPEG LA terminology. Did you mean a Temporal Unit=
 (TU)
? In AV1 a TU represent 1 displayable picture, just like AU in H.264 (if yo=
u
ignore interlaced video).

> +        The encoder generates one Access Unit per buffer. This format is
> +        adapted for stateful video decoders. AV1 (AOMedia Video 1) is an
> +        open video coding format. It was developed as a successor to VP9
> +        by the Alliance for Open Media (AOMedia).
> =20
>  .. raw:: latex
> =20
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-co=
re/v4l2-ioctl.c
> index c314025d977e..fc0f43228546 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1497,6 +1497,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *f=
mt)
>  		case V4L2_PIX_FMT_MT21C:	descr =3D "Mediatek Compressed Format"; break=
;
>  		case V4L2_PIX_FMT_QC08C:	descr =3D "QCOM Compressed 8-bit Format"; bre=
ak;
>  		case V4L2_PIX_FMT_QC10C:	descr =3D "QCOM Compressed 10-bit Format"; br=
eak;
> +		case V4L2_PIX_FMT_AV1:		descr =3D "AV1"; break;
>  		default:
>  			if (fmt->description[0])
>  				return;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev=
2.h
> index 01e630f2ec78..c5ea9f38d807 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -738,6 +738,7 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_FWHT_STATELESS     v4l2_fourcc('S', 'F', 'W', 'H') =
/* Stateless FWHT (vicodec) */
>  #define V4L2_PIX_FMT_H264_SLICE v4l2_fourcc('S', '2', '6', '4') /* H264 =
parsed slices */
>  #define V4L2_PIX_FMT_HEVC_SLICE v4l2_fourcc('S', '2', '6', '5') /* HEVC =
parsed slices */
> +#define V4L2_PIX_FMT_AV1      v4l2_fourcc('A', 'V', '1', '0') /* AV1 */
> =20
>  /*  Vendor-specific formats   */
>  #define V4L2_PIX_FMT_CPIA1    v4l2_fourcc('C', 'P', 'I', 'A') /* cpia1 Y=
UV */
>=20
> base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868