Re: [PATCH] media: v4l2-ctrls: Add encoded frame quality controls

[majja@codeaurora.org]

Hi,

Regarding below patch -

HEIF/HEIC image encoding uses HEVC/AVC encoders and client can set image 
quality level using
V4L2_CID_MPEG_VIDEO_FRAME_QUALITY control.

Reference BITRATE_MODE_CQ at
https://developer.android.com/reference/android/media/MediaCodecInfo.EncoderCapabilities#BITRATE_MODE_CQ

Regards,
     Maheshwar.


On 2020-05-18 14:07, Maheshwar Ajja wrote:
> When frame quality control is enabled encoder will choose
> the appropriate quantization parameter and bitrate to
> produce the client requested frame quality level.
> When frame quality control is disabled then frame quality
> is decided based on appropriate controls (i.e.
> V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE and/or
> V4L2_CID_MPEG_VIDEO_BITRATE_MODE)
> 
> Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>
> ---
>  .../userspace-api/media/v4l/ext-ctrls-codec.rst          | 16 
> ++++++++++++++++
>  drivers/media/v4l2-core/v4l2-ctrls.c                     |  3 +++
>  include/uapi/linux/v4l2-controls.h                       |  2 ++
>  3 files changed, 21 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index d0d506a..495b39b 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -1081,6 +1081,22 @@ enum v4l2_mpeg_video_h264_entropy_mode -
>      Macroblock level rate control enable. Applicable to the MPEG4 and
>      H264 encoders.
> 
> +``V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE (boolean)``
> +    Encoded frame quality control enable. If this control is enabled 
> then
> +    the quality level of the encoded frame is set with control
> +    ``V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY``. If this control is 
> disabled
> +    then the quality level of encoded frame is adjusted with 
> appropriate
> +    controls (e.g. ``V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE`` or
> +    ``V4L2_CID_MPEG_VIDEO_BITRATE_MODE``). Applicable to encoders.
> +
> +``V4L2_CID_MPEG_VIDEO_FRAME_QUALITY (integer)``
> +    Encoded frame quality control. If the control
> +    ``V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE`` is enabled then the
> +    quality of encoded frame is set with this control. Valid range is 
> 1 to
> +    100 where 1 indicates lowest quality and 100 indicates highest 
> quality.
> +    Encoder will decide the appropriate quantization parameter and 
> bitrate
> +    to produce requested frame quality. Applicable to encoders.
> +
>  ``V4L2_CID_MPEG_VIDEO_MPEG4_QPEL (boolean)``
>      Quarter pixel motion estimation for MPEG4. Applicable to the MPEG4
>      encoder.
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 1c617b4..1477198 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -982,6 +982,8 @@ const char *v4l2_ctrl_get_name(u32 id)
>  	case V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS:		return "HEVC Slice 
> 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";
> +	case V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE:		return "Frame Quality 
> Enable";
> +	case V4L2_CID_MPEG_VIDEO_FRAME_QUALITY:			return "Frame Quality";
> 
>  	/* CAMERA controls */
>  	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
> @@ -1178,6 +1180,7 @@ void v4l2_ctrl_fill(u32 id, const char **name,
> enum v4l2_ctrl_type *type,
>  	case V4L2_CID_FLASH_READY:
>  	case V4L2_CID_MPEG_VIDEO_DECODER_MPEG4_DEBLOCK_FILTER:
>  	case V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE:
> +	case V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE:
>  	case V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE:
>  	case V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE:
>  	case V4L2_CID_MPEG_VIDEO_H264_8X8_TRANSFORM:
> diff --git a/include/uapi/linux/v4l2-controls.h
> b/include/uapi/linux/v4l2-controls.h
> index 0ba1005..d97a934 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -742,6 +742,8 @@ enum v4l2_cid_mpeg_video_hevc_size_of_length_field 
> {
>  #define V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L6_BR	(V4L2_CID_MPEG_BASE 
> + 642)
>  #define V4L2_CID_MPEG_VIDEO_REF_NUMBER_FOR_PFRAMES	(V4L2_CID_MPEG_BASE 
> + 643)
>  #define V4L2_CID_MPEG_VIDEO_PREPEND_SPSPPS_TO_IDR	(V4L2_CID_MPEG_BASE 
> + 644)
> +#define V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE	(V4L2_CID_MPEG_BASE + 
> 645)
> +#define V4L2_CID_MPEG_VIDEO_FRAME_QUALITY		(V4L2_CID_MPEG_BASE + 646)
> 
>  /*  MPEG-class control IDs specific to the CX2341x driver as defined 
> by V4L2 */
>  #define V4L2_CID_MPEG_CX2341X_BASE				(V4L2_CTRL_CLASS_MPEG | 0x1000)