[FFmpeg-devel] [PATCH 3/5] lavc/libkvazaar: export encoded frame stats

[mypopy at gmail.com]

On Sun, Aug 9, 2020 at 6:07 AM Mark Thompson <sw at jkqxz.net> wrote:
>
> On 26/07/2020 13:26, Jun Zhao wrote:
> > From: Jun Zhao <barryjzhao at tencent.com>
> >
> > Export choosen pict_type and qp.
> >
> > Signed-off-by: Jun Zhao <barryjzhao at tencent.com>
> > ---
> >   libavcodec/libkvazaar.c | 30 ++++++++++++++++++++++++++++++
> >   1 file changed, 30 insertions(+)
> >
> > diff --git a/libavcodec/libkvazaar.c b/libavcodec/libkvazaar.c
> > index 71c9c8f..9032547 100644
> > --- a/libavcodec/libkvazaar.c
> > +++ b/libavcodec/libkvazaar.c
> > @@ -37,6 +37,7 @@
> >
> >   #include "avcodec.h"
> >   #include "internal.h"
> > +#include "packet_internal.h"
> >
> >   typedef struct LibkvazaarContext {
> >       const AVClass *class;
> > @@ -170,6 +171,7 @@ static int libkvazaar_encode(AVCodecContext *avctx,
> >       kvz_data_chunk *data_out = NULL;
> >       uint32_t len_out = 0;
> >       int retval = 0;
> > +    int pict_type;
> >
> >       *got_packet_ptr = 0;
> >
> > @@ -257,6 +259,34 @@ static int libkvazaar_encode(AVCodecContext *avctx,
> >               avpkt->flags |= AV_PKT_FLAG_KEY;
> >           }
> >
> > +        switch (frame_info.slice_type) {
> > +        case KVZ_SLICE_I:
> > +            pict_type = AV_PICTURE_TYPE_I;
> > +            break;
> > +        case KVZ_SLICE_P:
> > +            pict_type = AV_PICTURE_TYPE_P;
> > +            break;
> > +        case KVZ_SLICE_B:
> > +            pict_type = AV_PICTURE_TYPE_B;
> > +            break;
> > +        default:
> > +            av_log(avctx, AV_LOG_ERROR, "Unknown picture type encountered.\n");
> > +            return AVERROR_EXTERNAL;
> > +        }
> > +#if FF_API_CODED_FRAME
> > +FF_DISABLE_DEPRECATION_WARNINGS
> > +        avctx->coded_frame->pict_type = pict_type;
> > +FF_ENABLE_DEPRECATION_WARNINGS
> > +#endif
>
> Is there some value to setting the deprecated fields?  They will disappear on the next version bump, which probably isn't very far away.
>
I think we can keep this part, if we want to remove the
avctx->coded_frame->pict_type from next version bump, we can drop this
part from all codec one-time
> > +
> > +        ff_side_data_set_encoder_stats(avpkt, frame_info.qp * FF_QP2LAMBDA, NULL, 0, pict_type);
>
> I'm not familiar with kvazaar - is the QP value here actually reflective of the global quality in a useful way?  The documentation is not very good...
>
Yes, it's a global quality based on Frame in kvazaar

> (Your following patch for OpenH264 uses a field "AverageFrameQP", which has an much more usefully-suggestive name.)
>
> Zero is a valid QP value, but you shouldn't be passing it here.  Possibly it needs some more scaling to get the range to [1, FF_LAMDBA_MAX].
>
I know vpx encoder wrapper used the zero QP value in side data, maybe
we can keep the same action
> > +
> > +#if FF_API_CODED_FRAME
> > +FF_DISABLE_DEPRECATION_WARNINGS
> > +        avctx->coded_frame->quality = frame_info.qp * FF_QP2LAMBDA;
> > +FF_ENABLE_DEPRECATION_WARNINGS
> > +#endif
> > +
> >           *got_packet_ptr = 1;
> >       }
> >
> >
> - Mark