[FFmpeg-devel] [RFC] Add duration info to AVFrame

[Michael Niedermayer]

On Fri, Jun 01, 2012 at 11:14:04AM +0200, Stefano Sabatini wrote:
> On date Thursday 2012-03-08 15:50:21 +0100, Stefano Sabatini encoded:
> > Hi,
> > 
> > the feature would be useful for different purposes, especially for
> > normalization/correction timestamp filters (e.g. setpts).
> > 
> > Different approaches:
> > 
> > 1. I could export pkt_duration in AVFrame, like it is done with
> >    pkt_pts, duration is expressed in stream time_base units.
> > 
> >    This alone is not sufficient, because to decode pkt* things we need
> >    to reference the AVStream, which is not always available.
> > 
> > 2. I create a duration field in AVFrame, with no specified timebase,
> >    which is done for passing the duration information between
> >    different layers (e.g. lavc -> lavfi -> lavc), similar to what we
> >    did for pts.
> >    Then I could add a time_base unit in AVFrame, which is used for
> >    specifying the PTS and duration timebase.
> > 
> > 3. a combination of 1/2
> > 
> > Comments are welcome.
> 
> Done like 1.
> 
> Problems: 
> * as mentioned, pkt_pts alone can't be interpreted if there is no
>   reference to the stream timebase.

> * it is not possible to distinguish between duration=0 and
>   duration=unknown, because 0 == unknown, which depends on how
>   duration is defined in AVPacket.
>   Otherwise: would it make sense to change the semantics in AVPacket
>   (unknown=-1)?

when/where does something have a duration of 0 ?

the patch LGTM

[...]


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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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