On 16/06/2020 22:14, Stanimir Varbanov wrote:
> From: Maheshwar Ajja <majja@xxxxxxxxxxxxxx>
>
> When V4L2_CID_MPEG_VIDEO_BITRATE_MODE value is
> V4L2_MPEG_VIDEO_BITRATE_MODE_CQ, encoder will produce
> constant quality output indicated by
> V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY control value.
> Encoder will choose appropriate quantization parameter
> and bitrate to produce requested frame quality level.
>
> Signed-off-by: Maheshwar Ajja <majja@xxxxxxxxxxxxxx>
> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Thanks!
Hans
> ---
> .../userspace-api/media/v4l/ext-ctrls-codec.rst | 10 ++++++++++
> drivers/media/v4l2-core/v4l2-ctrls.c | 2 ++
> include/uapi/linux/v4l2-controls.h | 2 ++
> 3 files changed, 14 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index d0d506a444b1..b9d3f7ae6486 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -581,6 +581,8 @@ enum v4l2_mpeg_video_bitrate_mode -
> - Variable bitrate
> * - ``V4L2_MPEG_VIDEO_BITRATE_MODE_CBR``
> - Constant bitrate
> + * - ``V4L2_MPEG_VIDEO_BITRATE_MODE_CQ``
> + - Constant quality
>
>
>
> @@ -592,6 +594,14 @@ enum v4l2_mpeg_video_bitrate_mode -
> the average video bitrate. It is ignored if the video bitrate mode
> is set to constant bitrate.
>
> +``V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY (integer)``
> + Constant quality level control. This control is applicable when
> + ``V4L2_CID_MPEG_VIDEO_BITRATE_MODE`` value is
> + ``V4L2_MPEG_VIDEO_BITRATE_MODE_CQ``. 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.
> +
> ``V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION (integer)``
> For every captured frame, skip this many subsequent frames (default
> 0).
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 3f3fbcd60cc6..bc00d02e411f 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -200,6 +200,7 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
> static const char * const mpeg_video_bitrate_mode[] = {
> "Variable Bitrate",
> "Constant Bitrate",
> + "Constant Quality",
> NULL
> };
> static const char * const mpeg_stream_type[] = {
> @@ -832,6 +833,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_MPEG_VIDEO_GOP_CLOSURE: return "Video GOP Closure";
> case V4L2_CID_MPEG_VIDEO_PULLDOWN: return "Video Pulldown";
> case V4L2_CID_MPEG_VIDEO_BITRATE_MODE: return "Video Bitrate Mode";
> + case V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY: return "Constant Quality";
> case V4L2_CID_MPEG_VIDEO_BITRATE: return "Video Bitrate";
> case V4L2_CID_MPEG_VIDEO_BITRATE_PEAK: return "Video Peak Bitrate";
> case V4L2_CID_MPEG_VIDEO_TEMPORAL_DECIMATION: return "Video Temporal Decimation";
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 62271418c1be..0f7e4388dcce 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -375,6 +375,7 @@ enum v4l2_mpeg_video_aspect {
> enum v4l2_mpeg_video_bitrate_mode {
> V4L2_MPEG_VIDEO_BITRATE_MODE_VBR = 0,
> V4L2_MPEG_VIDEO_BITRATE_MODE_CBR = 1,
> + V4L2_MPEG_VIDEO_BITRATE_MODE_CQ = 2,
> };
> #define V4L2_CID_MPEG_VIDEO_BITRATE (V4L2_CID_MPEG_BASE+207)
> #define V4L2_CID_MPEG_VIDEO_BITRATE_PEAK (V4L2_CID_MPEG_BASE+208)
> @@ -742,6 +743,7 @@ 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_CONSTANT_QUALITY (V4L2_CID_MPEG_BASE + 645)
>
> /* MPEG-class control IDs specific to the CX2341x driver as defined by V4L2 */
> #define V4L2_CID_MPEG_CX2341X_BASE (V4L2_CTRL_CLASS_MPEG | 0x1000)
>
