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.
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
