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2004-04-21, 13:11
I have seen this too, and my theory is this; though it's just guessing:
If the opening chord of any song is simple (not complex) in structure, a low
bitrate will be used for that moment.
If the length of the song is calculated from only the beginning of the song,
the length guess will be quite wrong. I've seen 5 minute tracks starting
with a 4 kbps bitrate (I'm an ambient music freak :-), and estimated to last
for over 30 minutes..

Peter


> Charles Stanton wrote:
> > I noticed that on some mp3s that were ripped with Lame (vbr) I am
> > getting wildly off bitrates and song duration values (like
> 32 kpbs for a
> > file that is more like 320) and durations of 40 minutes for a four
> > minute song. I played the same mp3s on windows media
> player and it did
> > report the correct values...I am running 5.1.4 on a slimp3.
> >
> >
> >
> > Has anyone else seen this? Thx.
> >

Stewart Loving-Gibbard
2004-04-21, 17:38
I haven't looked into how the Perl module calculates VBR file lengths,
but there is something worth mentioning: the Xing VBR header.

The VBR header is an optional structure placed in a VBR MP3 file that
calculates the actual play length of the file. Since it is optional,
you sometimes find VBR files whose length and bitrate fluctuates wildly
in Winamp, for example. If you fix or add the VBR headers with an
appropriate tool (I use MP3 Tag Studio, mostly out of habit), players
that support it will read this tag and do a better job of displaying
play time.

Perhaps this is involved in the problem. Do the files in question have
proper VBR headers?

- Stew

slim (AT) vcooten (DOT) nl wrote:
> I have seen this too, and my theory is this; though it's just guessing:
> If the opening chord of any song is simple (not complex) in structure, a low
> bitrate will be used for that moment.
> If the length of the song is calculated from only the beginning of the song,
> the length guess will be quite wrong. I've seen 5 minute tracks starting
> with a 4 kbps bitrate (I'm an ambient music freak :-), and estimated to last
> for over 30 minutes..