[FFmpeg-devel] [PATCH 3/3] lavc: adjust timestamp in case of skiping initial samples

[Michael Niedermayer]

On Fri, Jul 13, 2012 at 12:18:54AM +0200, Nicolas George wrote:
> Le quintidi 25 messidor, an CCXX, Michael Niedermayer a écrit :
> > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > ---
> >  libavcodec/utils.c |    6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> > index e435c05..db0d870 100644
> > --- a/libavcodec/utils.c
> > +++ b/libavcodec/utils.c
> > @@ -1656,6 +1656,12 @@ int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
> >              } else {
> >                  av_samples_copy(frame->extended_data, frame->extended_data, 0, avctx->internal->skip_samples,
> >                                  frame->nb_samples - avctx->internal->skip_samples, avctx->channels, frame->format);
> > +                if(avctx->pkt_timebase.num && avctx->sample_rate) {
> > +                    if(frame->pkt_pts!=AV_NOPTS_VALUE)
> > +                        frame->pkt_pts += av_rescale_q(avctx->internal->skip_samples,(AVRational){1, avctx->sample_rate}, avctx->pkt_timebase);
> > +                    if(frame->pkt_dts!=AV_NOPTS_VALUE)
> > +                        frame->pkt_dts += av_rescale_q(avctx->internal->skip_samples,(AVRational){1, avctx->sample_rate}, avctx->pkt_timebase);
> > +                }
> >                  frame->nb_samples -= avctx->internal->skip_samples;
> >                  avctx->internal->skip_samples = 0;
> >              }
> 
> Altering the pkt_?ts fields feels a bit like lying: the packet did not have
> that altered timestamp. Maybe best_effort_timestamp would be a better
> choice:

the concern i have with best_effort_timestamp is that it was intended
to be a optional thing for applications not the one and only way to get
timestamps but if the initial sample skip just modifies it then
it becomes pretty much mandatory to be used

[...]


-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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