[FFmpeg-devel] [PATCH] avcodec/libvpxenc: enable dynamic max quantizer parameter reconfiguration

[James Zern]

Lynne,


On Wed, Mar 16, 2022 at 5:39 AM Lynne <dev at lynne.ee> wrote:
>
> 16 Mar 2022, 13:07 by danilchap-at-google.com at ffmpeg.org:
>
> > ---
> >  libavcodec/libvpxenc.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
> > index 8f94ba15dc..45baeed435 100644
> > --- a/libavcodec/libvpxenc.c
> > +++ b/libavcodec/libvpxenc.c
> > @@ -1658,6 +1658,13 @@ static int vpx_encode(AVCodecContext *avctx, AVPacket *pkt,
> >  flags |= strtoul(en->value, NULL, 10);
> >  }
> >
> > +            en = av_dict_get(frame->metadata, "max-quantizer", NULL, 0);
> > +            if (en) {
> > +                struct vpx_codec_enc_cfg cfg = *enccfg;
> > +                cfg.rc_max_quantizer = strtoul(en->value, NULL, 10);
> > +                vpx_codec_enc_config_set(&ctx->encoder, &cfg);
> > +            }
> >
>
> I was going to NAK the earlier patch, but forgot.
> Please think of a better way than stuffing random data in
> inappropriate fields, and fix the earlier patch that was mistakenly
> merged to not do that.

I agree this isn't great. Would you suggest updating the qmax setting
and checking it / all options on a per-frame basis or is there a
better way to reconfigure the codec on the fly?