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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Nicolas,

Le mercredi 24 avril 2024 à 12:03 +0200, Hans Verkuil a écrit :
On 29/03/2024 10:23, Ming Qian wrote:
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.

qp -> QP

Why is this applicable to H264/HEVC only? I think it is fine for any codec.

Same question, though we should document the range, which will differ per-
codecs. We should also document to always use the specified range, rather then a
HW custom range. This way we don't endup with issues we have hit with other ill-
defined controls.

Nicolas

Thanks for the tip, I will add a description of the value range in V3
patch.




This needs to document that the value applies to the last dequeued buffer
(VIDIOC_DQBUF).

+
  .. 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";

value -> Value

Also move it up two lines so that it follows V4L2_CID_MPEG_VIDEO_USE_LTR_FRAMES
rather than FWHT controls.

/* 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;

Drop the volatile flag, this isn't a volatile value.

+		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)

Regards,

	Hans






[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]

  Powered by Linux