[vox-tech] Mp3 Stereo to mono

[Alex Mandel]

So I've got a recording originally encoded as stereo even though there 
was only a mono mic. How can I easily strip off the second channel.
I tried lame:
$lame -m m --mp3input AUDI0001.MP3 AUDI0001e.MP3
and it does result in a mono file 1/2 the size but...

LAME version 3.96.1 (http://lame.sourceforge.net/)
Autoconverting from stereo to mono. Setting encoding to mono mode.
Using polyphase lowpass filter, transition band: 16538 Hz - 17071 Hz
Encoding AUDI0001.MP3 to AUDI0001b.MP3
Encoding as 44.1 kHz  64 kbps single-ch MPEG-1 Layer III (11x) qval=3
     Frame          |  CPU time/estim | REAL time/estim | play/CPU |    ETA
   1175/1150  (100%)|    0:01/    0:01|    0:01/    0:01|   19.304x|    0:00
average:  64.0 kbps

Writing LAME Tag...done
ReplayGain: +5.3dB

I'm afraid that the lowpass filter and ReplayGain may be messing with 
the actual audio. Also it's unclear wether its merging channels or 
eliminating 1 channel. I need to simply eliminate 1 not merge.

Based on info on this page Bladeenc can do it, but I didn't find it in 
the Ubunutu Repositories at all.
http://www.faqs.org/docs/Linux-HOWTO/MP3-HOWTO.html

Any suggestions on this are quite welcome, keep in mind that these audio 
files are for analysis of bird songs in a scientific setting so any 
alteration of the actual original audio is unacceptable as we might lose 
valuable information from filters and adjustments.

Thanks, Alex

PS: The next challenge will be to time tag the files(maybe in the ID3), 
and remove the dead space between bird calls to save HD space... feel 
free to make suggestions, I'm not looking forward to handling 3 TB of 
mp3s at this point.