On Wed, Apr 15, 2015 at 11:08:02AM +0200, wm4 wrote: > On Tue, 14 Apr 2015 22:44:22 +0200 > Michael Niedermayer <michae...@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 ? > > https://0x0.st/AG.mp3 > > 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.)
how can this be tested ? ./ffmpeg -ss 0 -i AG.mp3 -flags +bitexact new.wav ./ffmpeg-ref -ss 0 -i AG.mp3 -flags +bitexact old.wav 52298dcb38185e665b1b6d184884dd3e new.wav 52298dcb38185e665b1b6d184884dd3e old.wav ./ffmpeg -ss 5 -i AG.mp3 -flags +bitexact new.wav ./ffmpeg-ref -ss 5 -i AG.mp3 -flags +bitexact old.wav b4b8f2a83924b48f3d25baa6b9b4f4a8 new.wav b4b8f2a83924b48f3d25baa6b9b4f4a8 old.wav [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I am the wisest man alive, for I know one thing, and that is that I know nothing. -- Socrates
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