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media: v4l2-ctrls: Add encoder constant quality control

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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@codeaurora.org>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Maheshwar Ajja 2020-05-23 03:05:26 +02:00 committed by Mauro Carvalho Chehab
parent 73d513e45a
commit 4ad1b0d410
3 changed files with 14 additions and 0 deletions
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10
Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
View file

@ -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).

2
drivers/media/v4l2-core/v4l2-ctrls.c
View file

@ -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";

2
include/uapi/linux/v4l2-controls.h
View file

@ -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)