Re-encode MP3s with lame (script)

**tgeer43** · September 9th, 2009

I'm formulating a simple 3-line shell script to batch re-encode MP3s to 128bps CBR using lame. The first line is to convert all spaces in the filenames to underscores:

Code:

for i in *.mp3; do mv "$i" `echo $i | tr ' ' '_'`; done

and it works just fine.

The second line does the actual bitrate conversion:

Code:

for x in `ls -1 *.mp3`; do lame -b 128 $x NEW-${x}; done

It works fine too but note that I'm prefixing the output filename with 'NEW-' to avoid the 'Input and output filenames are the same' error. What I'd really like to do is just overwrite the original file with the new one using the original filename if possible.

Lastly I'm attempting to change the underscores in the filenames back to spaces. I thought I could just reverse the two SET parameters (" " and "_") from the first line to reverse the procedure. When I do that I get an error message that I don't understand. For example, if the current filename is:

"NEW-01._Led_Zeppelin_-_Black_Dog.mp3"

and I run the command:

Code:

for i in *.mp3; do mv "$i" `echo $i | tr '_' ' '`; done

I get the following error message:

mv: target `Dog.mp3' is not a directory

So why is the filename getting truncated to only the last word and why is 'mv' expecting a directory name?

Any help would be appreciated.

tgeer

**mc4man** · September 9th, 2009

If you wish to do this way (you'll lose tags) then this may be more suitable - doesn't care about spaces ect.

Code:

#!/bin/bash
mkdir save
for f in *.mp3; do lame -b 128 "$f" ./save/"${f%.mp3}.mp3"; done
rm *.mp3

You may want to not use the rm and confirm first, then remove .mp3's from prompt.

While not needed here this may work better for the underscore deal

# Rename to remove all strange chars

Code: