[FFmpeg-devel] -async

Michael Niedermayer michaelni at gmx.at
Sat May 19 21:23:12 CEST 2012

On Sat, May 19, 2012 at 08:11:50PM +0200, Clément Bœsch wrote:
> On Sat, May 19, 2012 at 07:59:24PM +0200, Michael Niedermayer wrote:
> > Hi everyone
> > 
> > async is finally back. The new implementation is different from both
> > our old and libavs.
> > I sadly couldnt just take libavs as it
> > 1. it didnt work in ffmpeg for unknown reasons
> > 2. it needs a seperate resampler meaning half speed and
> > 3. twice the quality loss
> > these would have been steps backward from ffmpegs previous -async
> > 
> > our new async is implemented completely in libswresample which means
> > its also trivially available to all other projects that use
> > libswresample. Just pass timestamps into swr and the user can via
> > AVOptions configure swr to do the ts sync compensation as he prefers.
> > -async X is also turned into an appropriate filter injection by
> > ffmpeg.c
> > 
> Nice. What's going to happen to asyncts filter? is it still required?

asyncts should be redundant

> Also, some documentation updates on the aresample filter (in
> doc/filters.texi) would be very welcome :)

swresample.c: options[] should contain all the parameters except the
plain sample rate case for backward compatibility

do we have a volunteer to copy&paste + format for texi that ?
Iam happy to fill in anything thats unclear

> BTW, do you mind the attached patch? (the macro might need some
> improvement if we really want to print the user argument)

patch looks nice but yes i think printing the filters equivalent
argument would be quite interresting for some

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Awnsering whenever a program halts or runs forever is
On a turing machine, in general impossible (turings halting problem).
On any real computer, always possible as a real computer has a finite number
of states N, and will either halt in less than N cycles or never halt.
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