[PATCH 1/2] media: v4l2-ctrls: Add average qp control

[Ming Qian]

Add a control V4L2_CID_MPEG_VIDEO_AVERAGE_QP to report the average qp
value of current encoded frame.

Signed-off-by: Ming Qian <ming.qian@xxxxxxx>
---
 Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 4 ++++
 drivers/media/v4l2-core/v4l2-ctrls-defs.c                 | 5 +++++
 include/uapi/linux/v4l2-controls.h                        | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index 2a165ae063fb..cef20b3f54ca 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -1653,6 +1653,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
     Quantization parameter for a P frame for FWHT. Valid range: from 1
     to 31.
 
+``V4L2_CID_MPEG_VIDEO_AVERAGE_QP (integer)``
+    This read-only control returns the average qp value of the currently
+    encoded frame. Applicable to the H264 and HEVC encoders.
+
 .. raw:: latex
 
     \normalsize
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
index 8696eb1cdd61..88e86e4e539d 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
@@ -972,6 +972,7 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_MPEG_VIDEO_USE_LTR_FRAMES:		return "Use LTR Frames";
 	case V4L2_CID_FWHT_I_FRAME_QP:				return "FWHT I-Frame QP Value";
 	case V4L2_CID_FWHT_P_FRAME_QP:				return "FWHT P-Frame QP Value";
+	case V4L2_CID_MPEG_VIDEO_AVERAGE_QP:			return "Average QP value";
 
 	/* VPX controls */
 	case V4L2_CID_MPEG_VIDEO_VPX_NUM_PARTITIONS:		return "VPX Number of Partitions";
@@ -1507,6 +1508,10 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 		*max = 0xffffffffffffLL;
 		*step = 1;
 		break;
+	case V4L2_CID_MPEG_VIDEO_AVERAGE_QP:
+		*type = V4L2_CTRL_TYPE_INTEGER;
+		*flags |= V4L2_CTRL_FLAG_VOLATILE | V4L2_CTRL_FLAG_READ_ONLY;
+		break;
 	case V4L2_CID_PIXEL_RATE:
 		*type = V4L2_CTRL_TYPE_INTEGER64;
 		*flags |= V4L2_CTRL_FLAG_READ_ONLY;
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 99c3f5e99da7..974fd254e573 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -898,6 +898,8 @@ enum v4l2_mpeg_video_av1_level {
 	V4L2_MPEG_VIDEO_AV1_LEVEL_7_3 = 23
 };
 
+#define V4L2_CID_MPEG_VIDEO_AVERAGE_QP  (V4L2_CID_CODEC_BASE + 657)
+
 /*  MPEG-class control IDs specific to the CX2341x driver as defined by V4L2 */
 #define V4L2_CID_CODEC_CX2341X_BASE				(V4L2_CTRL_CLASS_CODEC | 0x1000)
 #define V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE		(V4L2_CID_CODEC_CX2341X_BASE+0)
-- 
2.43.0-rc1