Yesterday I had to convert a few mp3 files to wavs. I also needed to crop them a bit on both ends. This is how I did it:
mplayer -ss 0.5 -endpos 1:14 -ao pcm:file="newfile.wav" oldfile.mp3
This is how it works:
-ss says how many seconds of the file to skip at the start. If you don't know the time, but the number of bytes instead, use
-sb instead. Note that
-ss only works with seconds, but accepts fractional seconds.
-endpos says at what point to stop playing. This accepts time as
hh:mm:ss.ms or in bytes. If you specify only one number, it's seconds.
-ao is a special instruction that specifies a plugin, and everything following the plugin are plugin specific options.
pcm is the format for wave files. You could use any format you like.
mplayer -ao help will tell you which codecs are supported. I haven't figured out all the suboptions for
pcm yet.