BT and FLAC questions...

[twatts]

http://bt.etree.org/details.php?id=522676#startcomments


OK, this is weird, or maybe not...

I have this seed, same FFP. However, my FLACs have this additional note:

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FLAC v1.1.0 > WAV > FLAC v1.2.1
FLAC tags added with metaflac v1.2.1
by Jason Sobel
January 27, 2008
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Although the FLACs have the same name and FFP, BT sees them as different files, and I get errors...

I didn't realize there was a difference in FLAC versions and adding tags... Anybody else know anything about this???

Thanks,

Terry

[jasonsobel]

this is how I replied to Terry in a PM.  I'm posting here in case anyone else is interested...

Terry,

I just saw your comment on a Phish torrent at bt.etree, and I thought I'd respond to you directly.  Different version of FLAC compress at different ratios (generally, newer versions have better compression).  Of course, it's all lossless, so the FFP never changes.  The FFP is essentially just an md5 checksum of the audio portion of the file only.  So whatever FLAC version, compression level, tags added or not, etc, etc... as long as the audio itself doesn't change, the FFP will match.

Of course, for bit torrent, the software needs to transfer files exactly.  So even though the audio hasn't changed with the FLAC version change.  And even though the audio hasn't changed with the addition of metadata (FLAC tags), the external file that bit torrent sees is different.

Even if I hadn't changed the FLAC version, the addition of FLAC tags would have changed the external files and you wouldn't be able to help seed on bt.etree.  So when I go back and add tags to the FLAC files, I generally take the time to update the FLAC's to the latest version (and also check for SBE's and fix if necessary).

Hope this helps to explain things.
- Jason