batch mp3 quality degrading

[scyzoryk]

I have a lot of mp3s with vocal audio (just people speaking). Anyone know a good mp3-quality to convert to? I also need to know of a program that would batch-quality-degrade all my mp3 files.

Thanks.

[DSPguru]

what are you aiming for ?
less diskspace :) ?
less quality :( ?
better quality :o ?

[scyzoryk]

Have a folder full of mp3s, 938mb in total. Need to get them all onto a 650mb or 700mb CDRW. So I basically need to degrade quality until they all just fit.

[DSPguru]

how about converting stereo to mono ?

[scyzoryk]

what program can I use to do that in batch?

[DSPguru]

for batch mp3 to mp3 conversion, you can use BeSweet or WinLame.

a better format for voice compression is called Speex,
you can get the encoder+decoder+winamp plugins in here:
http://www.saunalahti.fi/~cse/html/other.html

and a batch mp3-to-speex encoder in here :
http://home.wanadoo.nl/~w.speek/multi.htm

you'll need to download mpg123, so it can first decode your mp3 files.

[scyzoryk]

I'm doing alright with WinLAME, but there isn't much of a filesize difference when I fool around with the settings. The mp3s are already 22050Hz, 32kbps... so all I can do is lower the Hz... which makes the filesize 0.99% smaller (1.10mb to 1.09mb)

928 * (99 percent) = 918.72

I'll try messing around with speechex, unless you have any good ideas I can do to modify the mp3s with WinLame to make the filesize smaller. Thanks for your help so far.

[scyzoryk]

SpeechEx didn't make a difference either. I guess you can't get much filesize off of a 22050Hz, 32kpbs mp3.

[Fr4nz]

Maybe you could try a lower bitrate, for example 24kbit/s.

If you use Lame then use the commandline "--alt-preset 24".