On 19/05/2020 04:05, Maheshwar Ajja wrote: > If V4L2_CID_MPEG_VIDEO_ENC_SKIP_FRAMES control is enabled > encoder can drop frames, if required, to achieve target bitrate > instead of modifying the quantization parameter which lowers > the encoded frame quality. > > Reference: 4.3.8.1 OMX_Video_ControlRateConstantSkipFrames > https://www.khronos.org/registry/OpenMAX-IL/specs/OpenMAX_IL_1_1_2_Specification.pdf > > Signed-off-by: Maheshwar Ajja <majja@xxxxxxxxxxxxxx> > --- > Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 7 +++++++ > drivers/media/v4l2-core/v4l2-ctrls.c | 2 ++ > include/uapi/linux/v4l2-controls.h | 1 + > 3 files changed, 10 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..bc9265d 100644 > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst > @@ -1081,6 +1081,13 @@ enum v4l2_mpeg_video_h264_entropy_mode - > Macroblock level rate control enable. Applicable to the MPEG4 and > H264 encoders. > > +``V4L2_CID_MPEG_VIDEO_ENC_SKIP_FRAMES (boolean)`` > + Encoder skip frames enable. This control is applicable only if > + ``V4L2_CID_MPEG_VIDEO_BITRATE_MODE`` control is set. If this control > + is enabled encoder can drop frames, if required, to achieve target > + bitrate instead of modifying the quantization parameter which lowers > + the encoded frame quality. It's a bit unclear for which bitrate modes this control is valid: only for MODE_CBR, or also for the constant quality bitrate mode? Or both? The phrase 'control is set' is meaningless for a menu control: it really is always 'set'. So that needs to be reworked so it is more explicit. Also note that there is an Exynos MFC control that appears to do something similar: V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE. To what extent does that overlap with the functionality proposed here? It looks like this proposed control is basically the equivalent of setting V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE to V4L2_MPEG_MFC51_FRAME_SKIP_MODE_LEVEL_LIMIT. So perhaps this MFC control should be promoted to a standard MPEG control instead of inventing a new control? Regards, Hans > + > ``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..d2cb766 100644 > --- a/drivers/media/v4l2-core/v4l2-ctrls.c > +++ b/drivers/media/v4l2-core/v4l2-ctrls.c > @@ -914,6 +914,7 @@ const char *v4l2_ctrl_get_name(u32 id) > case V4L2_CID_MPEG_VIDEO_FWHT_PARAMS: return "FWHT Stateless Parameters"; > 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_ENC_SKIP_FRAMES: return "Encoder Skip Frames"; > > /* VPX controls */ > case V4L2_CID_MPEG_VIDEO_VPX_NUM_PARTITIONS: return "VPX Number of Partitions"; > @@ -1180,6 +1181,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type, > case V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE: > case V4L2_CID_MPEG_VIDEO_FRAME_RC_ENABLE: > case V4L2_CID_MPEG_VIDEO_MB_RC_ENABLE: > + case V4L2_CID_MPEG_VIDEO_ENC_SKIP_FRAMES: > case V4L2_CID_MPEG_VIDEO_H264_8X8_TRANSFORM: > case V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_ENABLE: > case V4L2_CID_MPEG_VIDEO_MPEG4_QPEL: > diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h > index 0ba1005..d3bc015 100644 > --- a/include/uapi/linux/v4l2-controls.h > +++ b/include/uapi/linux/v4l2-controls.h > @@ -742,6 +742,7 @@ 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_ENC_SKIP_FRAMES (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) >
