[FFmpeg-devel] [RFC] libvorbis decoder wraper

Michael Niedermayer michaelni at gmx.at
Sat May 5 16:05:17 CEST 2012


On Sat, May 05, 2012 at 02:56:35PM +0200, Reimar Döffinger wrote:
> On Sat, May 05, 2012 at 10:57:25AM +0200, Michael Niedermayer wrote:
> > This puts the libvorbis wraper back (updated to todays API)
> > I needed this for the ogg/vorbis timestmp/seeking fixes. Not sure if it
> > should be applied or left for reference in the ML / a branch
> 
> I think one of the reasons for discarding it (besides avoiding what for
> almost all would be useless bloat - since it is not possible to have
> only the encoder without the decoder) is that it forces people to
> report and fix issues with the native decoder instead of just using
> libvorbis.

> I don't object to adding it back though, but be careful not to add
> extra dependencies in a default build, I think nowadays the vorbis
> encode and decode functions are in separate .so files?

The need for the following should be rechecked:

commit 3837d107b76138680ba450cc1bddc3dc9bd9b00e
Author: Diego Biurrun <diego at biurrun.de>
Date:   Tue Nov 6 00:26:32 2007 +0000

    Keep -lvorbis in libvorbis linker flags even when only used for encoding.
    Some libvorbis versions on some platforms (macports) fail to compile otherwise.

    Originally committed as revision 10932 to svn://svn.ffmpeg.org/ffmpeg/trunk



> Also I'd be curious what exactly you needed it for, how did you
> use it for the timestamp/seeking fixes?
> Why wasn't our decoder "good enough" for whatever you did?

I needed it because ogg-vorbis defines the granule position based on
"total samples encoded". That term is not well defined for a codec
based on a lapped transform and it could easily be that 2
implementations differ on the first and last frame handling.
so i needed the original ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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