Hi Hans,

For I frame min QP, if global min QP is set, the QP choose algorithm
should meet both of them, hence QP will >=
max(V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MIN_QP,
V4L2_CID_MPEG_VIDEO_H264_MIN_QP).
And this is also the same to the P frame and max QP.
I can add some description to describe this behavior in the document.

Thanks,
Fish


Hans Verkuil <hverkuil-ci...@xs4all.nl> 於 2019年1月30日 週三 下午3:57寫道:
>
> On 1/30/19 8:45 AM, Fish Lin wrote:
> > Add following V4L2 QP parameters for H.264:
> >  * V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MIN_QP
> >  * V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MAX_QP
> >  * V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MIN_QP
> >  * V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MAX_QP
> >
> > These controls will limit QP range for intra and inter frame,
> > provide more manual control to improve video encode quality.
>
> How will this interact with V4L2_CID_MPEG_VIDEO_H264_MIN/MAX_QP?
>
> Or are drivers supposed to have either V4L2_CID_MPEG_VIDEO_H264_MIN/MAX_QP
> or these new controls? If so, then that should be documented.
>
> Regards,
>
>         Hans
>
> >
> > Signed-off-by: Fish Lin <linf...@google.com>
> > ---
> > Changelog since v1:
> > - Add description in document.
> >
> >  .../media/uapi/v4l/extended-controls.rst         | 16 ++++++++++++++++
> >  drivers/media/v4l2-core/v4l2-ctrls.c             |  4 ++++
> >  include/uapi/linux/v4l2-controls.h               |  6 ++++++
> >  3 files changed, 26 insertions(+)
> >
> > diff --git a/Documentation/media/uapi/v4l/extended-controls.rst 
> > b/Documentation/media/uapi/v4l/extended-controls.rst
> > index 286a2dd7ec36..f5989fad34f9 100644
> > --- a/Documentation/media/uapi/v4l/extended-controls.rst
> > +++ b/Documentation/media/uapi/v4l/extended-controls.rst
> > @@ -1214,6 +1214,22 @@ enum v4l2_mpeg_video_h264_entropy_mode -
> >      Quantization parameter for an B frame for H264. Valid range: from 0
> >      to 51.
> >
> > +``V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MIN_QP (integer)``
> > +    Minimum quantization parameter for H264 I frame, to limit I frame
> > +    quality in a range. Valid range: from 0 to 51.
> > +
> > +``V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MAX_QP (integer)``
> > +    Maximum quantization parameter for H264 I frame, to limit I frame
> > +    quality in a range. Valid range: from 0 to 51.
> > +
> > +``V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MIN_QP (integer)``
> > +    Minimum quantization parameter for H264 P frame, to limit P frame
> > +    quality in a range. Valid range: from 0 to 51.
> > +
> > +``V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MAX_QP (integer)``
> > +    Maximum quantization parameter for H264 P frame, to limit P frame
> > +    quality in a range. Valid range: from 0 to 51.
> > +
> >  ``V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP (integer)``
> >      Quantization parameter for an I frame for MPEG4. Valid range: from 1
> >      to 31.
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c 
> > b/drivers/media/v4l2-core/v4l2-ctrls.c
> > index 5e3806feb5d7..e2b0af0d2283 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> > @@ -825,6 +825,10 @@ const char *v4l2_ctrl_get_name(u32 id)
> >       case V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_LAYER:return "H264 
> > Number of HC Layers";
> >       case V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_LAYER_QP:
> >                                                               return "H264 
> > Set QP Value for HC Layers";
> > +     case V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MIN_QP:           return "H264 
> > I-Frame Minimum QP Value";
> > +     case V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MAX_QP:           return "H264 
> > I-Frame Maximum QP Value";
> > +     case V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MIN_QP:           return "H264 
> > P-Frame Minimum QP Value";
> > +     case V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MAX_QP:           return "H264 
> > P-Frame Maximum QP Value";
> >       case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:              return "MPEG4 
> > I-Frame QP Value";
> >       case V4L2_CID_MPEG_VIDEO_MPEG4_P_FRAME_QP:              return "MPEG4 
> > P-Frame QP Value";
> >       case V4L2_CID_MPEG_VIDEO_MPEG4_B_FRAME_QP:              return "MPEG4 
> > B-Frame QP Value";
> > diff --git a/include/uapi/linux/v4l2-controls.h 
> > b/include/uapi/linux/v4l2-controls.h
> > index 3dcfc6148f99..9519673e6437 100644
> > --- a/include/uapi/linux/v4l2-controls.h
> > +++ b/include/uapi/linux/v4l2-controls.h
> > @@ -533,6 +533,12 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type {
> >  };
> >  #define V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_LAYER   
> > (V4L2_CID_MPEG_BASE+381)
> >  #define V4L2_CID_MPEG_VIDEO_H264_HIERARCHICAL_CODING_LAYER_QP        
> > (V4L2_CID_MPEG_BASE+382)
> > +
> > +#define V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MIN_QP      
> > (V4L2_CID_MPEG_BASE+390)
> > +#define V4L2_CID_MPEG_VIDEO_H264_I_FRAME_MAX_QP      
> > (V4L2_CID_MPEG_BASE+391)
> > +#define V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MIN_QP      
> > (V4L2_CID_MPEG_BASE+392)
> > +#define V4L2_CID_MPEG_VIDEO_H264_P_FRAME_MAX_QP      
> > (V4L2_CID_MPEG_BASE+393)
> > +
> >  #define V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP (V4L2_CID_MPEG_BASE+400)
> >  #define V4L2_CID_MPEG_VIDEO_MPEG4_P_FRAME_QP (V4L2_CID_MPEG_BASE+401)
> >  #define V4L2_CID_MPEG_VIDEO_MPEG4_B_FRAME_QP (V4L2_CID_MPEG_BASE+402)
> >
>


-- 
Fish Lin | Software Engineer | linf...@google.com | +886-921-925519

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