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>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
---
.../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)
--
2.17.1
