[FFmpeg-devel] [PATCH 0/5] Fix mp3 gapless support (second try)

wm4 nfxjfg at googlemail.com
Wed Apr 15 11:08:02 CEST 2015

On Tue, 14 Apr 2015 22:44:22 +0200
Michael Niedermayer <michaelni at gmx.at> wrote:

> On Tue, Apr 14, 2015 at 09:24:32PM +0200, wm4 wrote:
> > Seeking was slightly broken. The 4th patch seems to fix this (everything
> > else is noise).
> > 
> > Note that ffmpeg can't correctly implement mp3 gapless audio if seeking
> > is used. The xing toc is not precise enough. The only way to fix it is
> > to do a full scan on the mp3 to index each frame (which in turn is not
> > possible with the public API, because byte seeking is not supported and
> > the parser would interfere anyway). But in this case, it even broke when
> > seeking to the beginning. I'm still not sure if this patch is correct.
> do you have a file/sample/testcase for patch 4 ?


I'm assuming mpg123 is getting it right. One test case is seeking to
the start of the file. (Seeking to anywhere else likely won't work,
because libavformat tries to use the imperfect xing toc, instead of
scanning the frames.)

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