[Lame-dev] [ lame-Bugs-968613 ] audio track inconsistent length in players

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Bugs item #968613, was opened at 2004-06-08 12:19
Message generated for change (Comment added) made by takehiro
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100290&aid=968613&group_id=290

Category: None
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: audio track inconsistent length in players

Initial Comment:
Sorry if this is a known problem; I'm new to LAME !

I first saw this problem in WinLame (which I think uses 
LAME 3.90, sorry I don't have it installed right now to 
check). I'm seeing what I think are varients of the 
problem under 3.94.

The basic problem is that when I try to play back an 
encoded MP3 file, the player often displays an incorrect 
length (time) for that track. 

Ex 1 : OS=Win2K, WinLame encoding a 5+ min WAV file 
at 256 kb/s. When played in WinAmp (5.02) or Windows 
Media Player (6.4.09.1109), the track appeared with a 
length of over 30 minutes. I think VBR was enabled but 
can't say for certain as I no longer have it installed and 
have migrated to the latest 3.94. I also don't know what 
the command line options looked like for this test - 
sorry !

Ex 2 : OS=Win2K, LAME 3.94. Encoded a 3:13 track at 
256 kb/s with VBR (-V 4 -B 320). I did this with both 
RazorLame (1.1.5.1342) and EAC (0.95 prebeta 5 8-
march-04). 
-Playback on WinAmp (5.02) showed a correct length of 
3:13. 
-Playback on Win2K with Windows Media Player 
(6.4.09.1109) showed a length of 6:23 (for EAC front 
end) and 6:22 (for RazorLame front end). 
-Playback on WinXP with Windows Media Player 
(8.00.00.4489) showed a bit rate of 620 kbps and a 
length of 1:19

Ex 3: WinAmp and Windows Media Player (XP and W2K) 
correctly display the track length when VBR is disabled 
(256 kbps).

In all cases where the track length was incorrectly 
reported, the media player would play through correctly 
and stop. However, if the players would get confused on 
any attempt to cue to a spot in the timeline of the track.

Since WinAmp seems to display the correct track length, 
it would be easy to blame this on Microsoft's media 
players. However since the problem is exposed only 
when VBR is enabled, it would seem to indicate that 
something else is also broken. Furthermore I was able to 
break WinAmp when using WinLame so the potential 
does seem to exist that it's more than just the MS 
players.

  lou (ll...@po...)

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>Comment By: Takehiro TOMINAGA (takehiro)
Date: 2005-02-26 16:52

Message:
Logged In: YES 
user_id=1071

Seems LAME before 3.95 has this bug, but now the problem 
is fixed.



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Comment By: Nobody/Anonymous (nobody)
Date: 2004-07-09 04:44

Message:
Logged In: NO 

I have XP Pro, winamp 5 pro, LAME v. 1.6.1

I had no problem ripping .mpc files everything went perfect. 
Then I tried .ogg files and I get this same error (weird track 
lengths) and also a decrease in audio quality (with highest 
settings available). Is my LAME old? Or what?

- Yale
yal...@3w...

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Comment By: Myers Carpenter (myers_carpenter)
Date: 2004-06-10 07:11

Message:
Logged In: YES 
user_id=335935

It's dead simple to compute the time on a non-vbr track. 
You just take the frame size and then look at the file
length and do some other simple math.

To compute a VBR file you really need a VBR header, or you
have to scan the whole file.  What it looks like is that the
VBR header is being misread by M$ products.  

It would be intresting to know what iTunes thinks the length is.

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