Re: Problem importing certain MP2 files

On Oct 18, 2006, at 1:58 AM, Markus Meyer wrote:
> I'm a developer of Audacity [1] and we use libmad to import MP2/MP3  
> files. While it generally works fine (thanks a bunch for the great  
> library!) there are some MP2 files libmad does not import (see [2]  
> for an example, about 4.4 MB). When trying to play this file with  
> madplay 0.15.2 on Ubuntu, the following output is given:
>
> markus@markus:~$ madplay nb00.mp2
> MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert  
> Leslie et al.
> error: frame 0: bad bitrate/mode combination
> 0 frames decoded (0:00:00,0), -inf dB peak amplitude, 0 clipped  
> samples
>
> The file does play fine with mplayer, though.
>
> Thanks for any response!
> Markus
>
> [1] http://audacity.sourceforge.net/
> [2] http://www.mesw.de/opensource/nb00.mp2

This file contains a 256 kbps single-channel Layer II stream.  
According to ISO/IEC 11172-3, "For Layer II, not all combinations of  
total bitrate and mode are allowed." The accompanying table shows  
that for 256 kbps Layer II streams, only stereo, intensity stereo,  
and dual channel modes are allowed.

This might, of course, be unnecessarily strict. I'll consider  
relaxing the restriction if I can determine no other potential  
adverse effects.

Thanks for the report,

-- 
Rob Leslie
[email protected]