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BUG wrong VBR bitrate

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BUG wrong VBR bitrate

by pyro pingvin :: Rate this Message:

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For some mp3 files I see a wrong VBR bitrate reported. Instead of e.g. ~253kbps, I see values like 128kbps (as if it's a CBR file)

Re: BUG wrong VBR bitrate

by Christian Grothoff :: Rate this Message:

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Hi!

Sorry for the late reply.  I've so far been unable to find a VBR mp3 to begin
with, which makes this problem harder for me to reproduce.  Furthermore, there
is an inherent limitation in how LE calculates VBRs, which is that it takes a
(limited) number of samples, not the entire file, for the calculation.  So if
you have a VBR mp3 that initially has roughly 128 kbps and later more, this
would still be the expected result (scanning the entire file is something I
would consider too expensive).

Now, the calculations done might be wrong, but they look fine -- and I'm not
an expert on mp3 to begin with.  If someone could show me where
mp3_extractor.c is wrong here (ideally with a sample mp3), I'll of course be
happy to look into this some more or integrate a patch.

Happy hacking,

Christian

On Saturday, October 23, 2010 11:01:11 am pyro pingvin wrote:
> For some mp3 files I see a wrong VBR bitrate reported. Instead of e.g.
> ~253kbps, I see values like 128kbps (as if it's a CBR file)