[FFmpeg-devel] [PATCH] flac demuxer: improve seeking

Rainer Hochecker rainer.hochecker at onlinehome.de
Mon Apr 14 09:57:25 CEST 2014


Michael Niedermayer <michaelni <at> gmx.at> writes:

> > 
> > I send an update to github
> > https://github.com/FFmpeg/FFmpeg/pull/64
> > 
> > The results are almost identical to original fate test.
> 
> why only almost ?
> is there a bug in the original?
> 
> we had more than one user ask for exact seeking (not related to flac)
> so iam a bit reluctant to worsen any seek functionality
> 
> also iam not sure calling av_read_frame() from read_timestamp() is a
> good idea. av_read_frame() is a quite big function with lots of stuff
> in it and the functions it calls
> Iam not saying its wrong, just doesnt look very pretty and probably
> makes understaning and debuging the code harder  ...
> 
> [...]

Yes, av_read_frame is not a good idea to use here. It does not give the
exact starting position which is the reason the results are slightly
different. Also the current parser sometimes returns eof after having set
file pos to some arbitrary position.
I think I need to write some function which syncs to starting point of a
header/packet. 




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