Re: [PATCH v2 2/2] media: v4l: Add H265 pixel format

[Nicolas Dufresne]

Le lundi 11 avril 2022 à 16:01 +0800, James_Lin a écrit :
> Add H265 pixel format.
> So driver can recognize external camera devices 
> whom use h265 to describe High Efficiency Video Coding method.
> 
> Signed-off-by: James_Lin <Ping-lei.Lin@xxxxxxxxxxxx>
> ---
>  .../userspace-api/media/v4l/pixfmt-compressed.rst      | 10 ++++++++++
>  drivers/media/v4l2-core/v4l2-ioctl.c                   |  1 +
>  include/uapi/linux/videodev2.h                         |  1 +
>  3 files changed, 12 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
> index 967fc803ef94..75292aafe2eb 100644
> --- a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
> +++ b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
> @@ -36,6 +36,16 @@ Compressed Formats
>        - MPEG multiplexed stream. The actual format is determined by
>  	extended control ``V4L2_CID_MPEG_STREAM_TYPE``, see
>  	:ref:`mpeg-control-id`.
> +    * .. _V4L2-PIX-FMT-H265:
> +
> +      - ``V4L2_PIX_FMT_H265``

Please name this V4L2_PIX_FMT_HEVC. This has been discussed few years ago,
related to the staging V4L2_PIX_FMT_HEVC_SLICE format (which is being worked on
to be taken out of staging). HEVC was preferred over H.265, so lets be
consistent now that decision has been made.

> +      - 'H265'
> +      - H.265 Access Unit.
> +	The decoder expects one Access Unit per buffer.
> +	The encoder generates one Access Unit per buffer.
> +	If :ref:`VIDIOC_ENUM_FMT` reports ``V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM``
> +	then the decoder has no	requirements since it can parse all the
> +	information from the raw bytestream.
>      * .. _V4L2-PIX-FMT-H264:
>  
>        - ``V4L2_PIX_FMT_H264``
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 96e307fe3aab..aeaeb29307a4 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1402,6 +1402,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>  		case V4L2_PIX_FMT_JPEG:		descr = "JFIF JPEG"; break;
>  		case V4L2_PIX_FMT_DV:		descr = "1394"; break;
>  		case V4L2_PIX_FMT_MPEG:		descr = "MPEG-1/2/4"; break;
> +		case V4L2_PIX_FMT_H265:		descr = "H.265"; break;
>  		case V4L2_PIX_FMT_H264:		descr = "H.264"; break;
>  		case V4L2_PIX_FMT_H264_NO_SC:	descr = "H.264 (No Start Codes)"; break;
>  		case V4L2_PIX_FMT_H264_MVC:	descr = "H.264 MVC"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 3768a0a80830..636e4236bfb8 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -691,6 +691,7 @@ struct v4l2_pix_format {
>  #define V4L2_PIX_FMT_JPEG     v4l2_fourcc('J', 'P', 'E', 'G') /* JFIF JPEG     */
>  #define V4L2_PIX_FMT_DV       v4l2_fourcc('d', 'v', 's', 'd') /* 1394          */
>  #define V4L2_PIX_FMT_MPEG     v4l2_fourcc('M', 'P', 'E', 'G') /* MPEG-1/2/4 Multiplexed */
> +#define V4L2_PIX_FMT_H265     v4l2_fourcc('H', '2', '6', '5') /* H265 with start codes */
>  #define V4L2_PIX_FMT_H264     v4l2_fourcc('H', '2', '6', '4') /* H264 with start codes */
>  #define V4L2_PIX_FMT_H264_NO_SC v4l2_fourcc('A', 'V', 'C', '1') /* H264 without start codes */
>  #define V4L2_PIX_FMT_H264_MVC v4l2_fourcc('M', '2', '6', '4') /* H264 MVC */