On Wed, Apr 15, 2015 at 01:16:45PM +0200, wm4 wrote: > On Wed, 15 Apr 2015 12:42:04 +0200 > Michael Niedermayer <michae...@gmx.at> wrote: > > > 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 > > The result is the same because in both cases the CBR seeking path is > used, which didn't change. You need to apply patch 5/5. I don't have a > good "real" VBR sample at hand for testing, unfortunately.
ok, i can confirm that seek to 0 works better with the patches 3&4 with xing TOC so applied them [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB If a bugfix only changes things apparently unrelated to the bug with no further explanation, that is a good sign that the bugfix is wrong.
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