[FFmpeg-devel] Exposing preroll and remainder info for aac and mp3.

Raymond Toy rtoy at google.com
Mon Jul 16 18:01:09 CEST 2012


On Sun, Jul 15, 2012 at 7:21 AM, Michael Niedermayer <michaelni at gmx.at>wrote:

> On Mon, Jul 09, 2012 at 11:08:07AM -0700, Dale Curtis wrote:
> > On Wed, Jul 4, 2012 at 2:21 PM, Michael Niedermayer <michaelni at gmx.at
> >wrote:
> >
> > >
> > > just posted a patchset implementing initial silence skiping for mp3
> > > doing the same with mov/mp4 aac should be trivial, id need a reference
> > > sample though to make sure the aac/mov/mp4 stuff is correct. Its easy
> > > to get it wrong without a testcase ...
> > >
> > > the mp3 code should be compatible with lames way of indicating the
> > > amount of padding.
> > >
> > >
> > Thanks Michael! The AAC audio files from the demo page are good samples:
> >
> > MP3:
> > http://rtoy.github.com/webaudio/codec-tests/resources/media/square3.mp3
>
> fixed initial silence skiping
>
>
> >
> > AAC:
> > http://rtoy.github.com/webaudio/codec-tests/resources/media/square3.m4a
>
> posted a patch that will fix the initial silence on this as well
> but this file is using just 1 of 3 ways by which mp4-aac can specify
> the initial silence.
>

Thanks for looking into this!


> Implementing the other 2 is trivial but i dont want to implement them
> without sample files to test with. It would have a high potential
> to introduce bugs (noone would notice if we are 5 samples off)
> do you happen to have samples that use the other variants ?
>

Unfortunately, no.  Can you provide some hints on what the other ways are?
 I'll try to look around to see if I can something that can produce them.

>
> ill look into the trailing silence soon
>

Really appreciate it!

Ray


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