[Vorbis] buggy vorbis encoder

[Ben Collver]

Good day,

I bought an iAudio G3 digital player from Cowon, and was disappointed 
when it failed to play some of my .ogg files.  After inspecting the 
individual files with ogginfo, patterns emerged.  All of the problem 
files were encoded with old libVorbis encoders, most circa 2001.

All of the problem files that caused the unit to lock up would report 
many lines of "Negative granulepos on vorbis stream outside of headers. 
This file was created by a buggy encoder."

All of the problem files that caused the unit to skip around and become 
unresponsive would report "Note: Stream 1 has serial number 0, which is 
legal but may cause problems with some tools."

Winamp and xmms play these files without problem.  Ogginfo detects the 
problems.  Do there exist tools to repair Vorbis streams with a minimum 
of quality loss?  Is my best bet to decode the bad streams and then 
re-encode them with a more recent libVorbis?

Thank you,

Ben