Re: [RFC/WIP 1/4] media: Add HEIC compressed pixel format

[Stanimir Varbanov <stanimir.varbanov@linaro.org>]

On 5/18/21 8:11 PM, Nicolas Dufresne wrote:
> Le jeudi 29 avril 2021 à 16:28 +0300, Stanimir Varbanov a écrit :
>> Add HEIC (High-Efficiency Image Container) pixel format. This an
>> image container which use HEVC codec to encoded images.
>>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
>> ---
>>  .../userspace-api/media/v4l/pixfmt-compressed.rst    | 12 ++++++++++++
>>  drivers/media/v4l2-core/v4l2-ioctl.c                 |  1 +
>>  include/uapi/linux/videodev2.h                       |  1 +
>>  3 files changed, 14 insertions(+)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
>> index ba6c0c961204..246bff90dcac 100644
>> --- a/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-compressed.rst
>> @@ -186,6 +186,18 @@ Compressed Formats
>>  	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-HEIC:
>> +
>> +      - ``V4L2_PIX_FMT_HEIC``
>> +      - 'HEIC'
>> +      - High Efficiency Image Container is an image container file format which
>> +        uses HEVC encoding and it is a variant of HEIF (High Efficiency Image File)
>> +        format.
> 
> Can you clarify, is it expected that an HEIF container be compatible or not ?
> Assuming this exist. The HEIC being a brand name, and not really a standard
> seems rather confusing. Is this is right name, or should you introduce HEIF with
> variant control, similar to HEVC profile control.


V4L2_PIX_FMT_HFIF_HEVC is a good option, I guess.

> 
> Speaking of profile, does it inherit anything from HEVC ? So we need to set HEVC
> pofile/level ? Is there some way's to affect the quality or is it the HEVC QP
> controls ?

V4L2_PIX_FMT_HFIF_HEVC will accept
V4L2_MPEG_VIDEO_HEVC_PROFILE_MAIN_STILL_PICTURE profile and the image
quality is set through V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY

> 
>>
>>
>> +	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-HEVC-SLICE:
>>  
>>        - ``V4L2_PIX_FMT_HEVC_SLICE``
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 31d1342e61e8..3a1b4c3a76c8 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -1454,6 +1454,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>>  		case V4L2_PIX_FMT_S5C_UYVY_JPG:	descr = "S5C73MX interleaved UYVY/JPEG"; break;
>>  		case V4L2_PIX_FMT_MT21C:	descr = "Mediatek Compressed Format"; break;
>>  		case V4L2_PIX_FMT_SUNXI_TILED_NV12: descr = "Sunxi Tiled NV12 Format"; break;
>> +		case V4L2_PIX_FMT_HEIC:		descr = "HEIC Image Format"; break;
>>  		default:
>>  			if (fmt->description[0])
>>  				return;
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 79dbde3bcf8d..2153b5c31d46 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -699,6 +699,7 @@ struct v4l2_pix_format {
>>  #define V4L2_PIX_FMT_FWHT     v4l2_fourcc('F', 'W', 'H', 'T') /* Fast Walsh Hadamard Transform (vicodec) */
>>  #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_HEIC	v4l2_fourcc('H', 'E', 'I', 'C') /* HEIC HEVC image format */
>>  
>>  /*  Vendor-specific formats   */
>>  #define V4L2_PIX_FMT_CPIA1    v4l2_fourcc('C', 'P', 'I', 'A') /* cpia1 YUV */
> 
> 

-- 
regards,
Stan