I have lame and sox installed. can I use them to compress an existing mp3 from 128 bit to 32 bit? how do I do that?

If its not possible, what software do I need?

I don't know if it's necessary to convert to .wav first, but you can do so with sox like this:

You can maybe omit all the options, but those will give you a standard CD-ready .wav file. Then use lame to convert back to .mp3:

Check the lame manual page ('man lame') for more options. You could probably tweak the quality settings to get better output, and unless the file actually needs to be a constant 32kbits/sec, you could probably use variable bitrate (-vbr option to lame) to get a little better quality with about the same file size.

thanks for the info wapcaplet.

is it possible to convert to wav all the mp3s in a directory all at one command?

is it also possible to compress it directly without having to convert it wav?

Sure enough, I just looked at the lame man page, and it has an option --mp3input, which says is for downsampling an existing mp3. So you're in luck!

Here's a way you can encode a bunch of files at once. Say you want to convert all the mp3s in the current directory, and put the new files in ./compressed. You'd do something like this:

(The double-quotes are to prevent problems with filenames containing spaces. If your filenames don't have spaces, you can leave the double-quotes out)

ok i got it!

thanks abunch for your help!