ogg dev - Jun 2009 - Fixing ogg vorbis corruption caused by bad metadata

Vorbose -v reports the following for the beginning of the file:

INFO   page: Capture pattern OggS, format version 0
             Flags: first page of logical stream

             Granule position: 0x0000000000000000
             Stream serialno : 0x490f5cff
             Sequence number : 0
             Checksum        : 0xee9c02b9
             Total segments  : 1
             Total packets   : 1 completed
                              ( 30)

info header: Vorbis identification header parsed:
             Stream version     : 0
             Output channels    : 2
             Output sample rate : 44100 Hz
             Bitrate targets    : unset/224000/unset
             Block sizes        : 256/2048 samples

WARN stream: 53638 bytes of garbage before page 1

info stream: All identification header pages parsed.
             1 logical stream muxed in this link.

INFO   page: Capture pattern OggS, format version 0
             Flags: packet continued from previous page

             Granule position: 0x0000000000000000
             Stream serialno : 0x490f5cff
             Sequence number : 13
             Checksum        : 0xab096acc
             Total segments  : 6
             Total packets   : 1 completed (1 cont)
                              (255, 255, 255, 255, 255, 113)

In short, this file's Ogg encapsulation is corrupt.  There's no chance
of this being a vorbis_comment_add_tag() bug as that would be corrupt
data inside valid Ogg.  The Ogg structure itself is invalid here.

Monty

Monty Montgomery wrote, on 6/25/2009 1:10 PM:
> Vorbose -v reports the following for the beginning of the file:
>
> INFO   page: Capture pattern OggS, format version 0
>               Flags: first page of logical stream
>
>               Granule position: 0x0000000000000000
>               Stream serialno : 0x490f5cff
>               Sequence number : 0
>               Checksum        : 0xee9c02b9
>               Total segments  : 1
>               Total packets   : 1 completed
>                                ( 30)
>
> info header: Vorbis identification header parsed:
>               Stream version     : 0
>               Output channels    : 2
>               Output sample rate : 44100 Hz
>               Bitrate targets    : unset/224000/unset
>               Block sizes        : 256/2048 samples
>
> WARN stream: 53638 bytes of garbage before page 1
>
> info stream: All identification header pages parsed.
>               1 logical stream muxed in this link.
>
> INFO   page: Capture pattern OggS, format version 0
>               Flags: packet continued from previous page
>
>               Granule position: 0x0000000000000000
>               Stream serialno : 0x490f5cff
>               Sequence number : 13
>               Checksum        : 0xab096acc
>               Total segments  : 6
>               Total packets   : 1 completed (1 cont)
>                                (255, 255, 255, 255, 255, 113)
>
> In short, this file's Ogg encapsulation is corrupt.  There's no
chance
> of this being a vorbis_comment_add_tag() bug as that would be corrupt
> data inside valid Ogg.  The Ogg structure itself is invalid here.
Is there any way to understand exactly how it is invalid? I can 
replicate this corruption simply by adding large album art to any ogg 
file with the latest release of MediaMonkey.

Adam

> Is there any way to understand exactly how it is invalid? I can replicate
> this corruption simply by adding large album art to any ogg file with the
> latest release of MediaMonkey.
The second page is corrupt.  The basic structure looks correct, first
guess would be bad checksum.  I'll look more closely in just a bit.
This might explain why some players might accept it--- if they're
ignoring checksumming and error detection.

Monty