Re: [PATCH] media: v4l2-ctrls: Add encoded frame quality controls

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Hi Hans,

Thank you for the suggestion. I will update the patch accordingly.

Regards,
    Maheshwar.


On 2020-05-18 23:45, Hans Verkuil wrote:
Hi Maheshwar,

On 18/05/2020 23:09, majja@xxxxxxxxxxxxxx wrote:
Hi,

Regarding below patch -

HEIF/HEIC image encoding uses HEVC/AVC encoders and client can set image
quality level using
V4L2_CID_MPEG_VIDEO_FRAME_QUALITY control.

Reference BITRATE_MODE_CQ at
https://developer.android.com/reference/android/media/MediaCodecInfo.EncoderCapabilities#BITRATE_MODE_CQ

So what you are really introducing here is a new enum
v4l2_mpeg_video_bitrate_mode
mode: V4L2_MPEG_VIDEO_BITRATE_MODE_CQ.

Why not just add that new mode, then add V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY
which is only used if the bitrate mode is MODE_CQ.

That builds nicely on top of the already existing
V4L2_CID_MPEG_VIDEO_BITRATE_MODE
control.

Regards,

	Hans


Regards,
     Maheshwar.


On 2020-05-18 14:07, Maheshwar Ajja wrote:
When frame quality control is enabled encoder will choose
the appropriate quantization parameter and bitrate to
produce the client requested frame quality level.
When frame quality control is disabled then frame quality
is decided based on appropriate controls (i.e.
V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE and/or
V4L2_CID_MPEG_VIDEO_BITRATE_MODE)

Signed-off-by: Maheshwar Ajja <majja@xxxxxxxxxxxxxx>
---
 .../userspace-api/media/v4l/ext-ctrls-codec.rst          | 16
++++++++++++++++
 drivers/media/v4l2-core/v4l2-ctrls.c                     |  3 +++
 include/uapi/linux/v4l2-controls.h                       |  2 ++
 3 files changed, 21 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index d0d506a..495b39b 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -1081,6 +1081,22 @@ enum v4l2_mpeg_video_h264_entropy_mode -
Macroblock level rate control enable. Applicable to the MPEG4 and
     H264 encoders.

+``V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE (boolean)``
+    Encoded frame quality control enable. If this control is enabled
then
+    the quality level of the encoded frame is set with control
+    ``V4L2_CID_MPEG_VIDEO_CONSTANT_QUALITY``. If this control is
disabled
+    then the quality level of encoded frame is adjusted with
appropriate
+    controls (e.g. ``V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE`` or
+    ``V4L2_CID_MPEG_VIDEO_BITRATE_MODE``). Applicable to encoders.
+
+``V4L2_CID_MPEG_VIDEO_FRAME_QUALITY (integer)``
+    Encoded frame quality control. If the control
+    ``V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE`` is enabled then the
+ quality of encoded frame is set with this control. 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. Applicable to encoders.
+
 ``V4L2_CID_MPEG_VIDEO_MPEG4_QPEL (boolean)``
Quarter pixel motion estimation for MPEG4. Applicable to the MPEG4
     encoder.
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
b/drivers/media/v4l2-core/v4l2-ctrls.c
index 1c617b4..1477198 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -982,6 +982,8 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS:		return "HEVC Slice
Parameters";
 	case V4L2_CID_MPEG_VIDEO_HEVC_DECODE_MODE:		return "HEVC Decode
Mode";
case V4L2_CID_MPEG_VIDEO_HEVC_START_CODE: return "HEVC Start Code"; + case V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE: return "Frame Quality
Enable";
+	case V4L2_CID_MPEG_VIDEO_FRAME_QUALITY:			return "Frame Quality";

 	/* CAMERA controls */
 	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
@@ -1178,6 +1180,7 @@ void v4l2_ctrl_fill(u32 id, const char **name,
enum v4l2_ctrl_type *type,
 	case V4L2_CID_FLASH_READY:
 	case V4L2_CID_MPEG_VIDEO_DECODER_MPEG4_DEBLOCK_FILTER:
 	case V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE:
+	case V4L2_CID_MPEG_VIDEO_FRAME_QUALITY_ENABLE:
 	case V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE:
 	case V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE:
 	case V4L2_CID_MPEG_VIDEO_H264_8X8_TRANSFORM:
diff --git a/include/uapi/linux/v4l2-controls.h
b/include/uapi/linux/v4l2-controls.h
index 0ba1005..d97a934 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -742,6 +742,8 @@ 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_FRAME_QUALITY_ENABLE (V4L2_CID_MPEG_BASE +
645)
+#define V4L2_CID_MPEG_VIDEO_FRAME_QUALITY (V4L2_CID_MPEG_BASE + 646)

 /*  MPEG-class control IDs specific to the CX2341x driver as defined
by V4L2 */
#define V4L2_CID_MPEG_CX2341X_BASE (V4L2_CTRL_CLASS_MPEG | 0x1000)



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