Re: [PATCH V2] [media] v4l2: Add AV1 pixel format

[Nicolas Dufresne]

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 août 2022 à 09:40 +0800, Shi Hao a écrit :
> From: "hao.shi" <hao.shi@xxxxxxxxxxx>
> 
> Add AV1 compressed pixel format. It is the more common format.
> 
> Signed-off-by: Hao Shi <hao.shi@xxxxxxxxxxx>
> ---
>  .../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(+)
> 
> 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 passed
>          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 you
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).
>  
>  .. raw:: latex
>  
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/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 *fmt)
>  		case V4L2_PIX_FMT_MT21C:	descr = "Mediatek Compressed Format"; break;
>  		case V4L2_PIX_FMT_QC08C:	descr = "QCOM Compressed 8-bit Format"; break;
>  		case V4L2_PIX_FMT_QC10C:	descr = "QCOM Compressed 10-bit Format"; break;
> +		case V4L2_PIX_FMT_AV1:		descr = "AV1"; break;
>  		default:
>  			if (fmt->description[0])
>  				return;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.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 */
>  
>  /*  Vendor-specific formats   */
>  #define V4L2_PIX_FMT_CPIA1    v4l2_fourcc('C', 'P', 'I', 'A') /* cpia1 YUV */
> 
> base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868