[ogg-dev] Fixing ogg vorbis corruption caused by bad metadata

Adam Rosi-Kessel adam at rosi-kessel.org
Thu Jun 25 20:50:56 PDT 2009


Monty Montgomery wrote, on 6/25/2009 3:23 PM:
> Confirmed--- the checksum on the second page (the comment page where
> the album art was added) is incorrect.  Vorbis players are not allowed
> to decode any stream in which one of the setup headers is corrupt, and
> a bad checksum counts as corrupt.
> Unfortunately, this means none of the remuxing ogg tools in our
> toolchains will touch those pages either; they will remux and fix most
> problems with valid pages, but a bad checksum usually means the page
> is toast, so they won't try.

I suppose this probably won't come to a surprise to anyone, but if I 
comment out the checksum checking in framing.c, I still can't decode 
these files. ogginfo gives a different offset for the "hole in data" and 
also these additional warnings:

Warning: sequence number gap in stream 1. Got page 13 when expecting 
page 2. Indicates missing data.
Warning: discontinuity in stream (1)

I didn't think the fix could be that simple, but I thought I'd mention 
my experiment.

Adam


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