The default Slackware install of SoX lacks MP3 support, presumably for legal reasons. You can actually get by without using SoX by falling back upon ffmpeg but SoX does have several nice features that might make it worth “fixing”.
Whether going to the trouble of re-compiling SoX is worth it or not is up to you. If you find your workflow does center around manipulating mp3 files from the terminal, then it's likely worth while. Otherwise, there are many other tools that you can fall back on just for MP3 files, using SoX for everything else.
Download the SoX source code from http://sox.sourceforge.net and Pat's SlackBuild script from your local Slackware mirror (for example,
Rebuild with as much codec support as you can manage. For example:
./configure --with-distro='SlackermediaXX' --with-ladspa-path='/usr/lib64/' --with-oggvorbis=dyn --with-flac=dyn --with-amrwb=dyn --with-amrnb=dyn --with-wavpack=dyn --with-alsa=dyn --with-ffmpeg=dyn --with-oss=dyn --with-sndfile=dyn --with-mp3=dyn --with-gsm=dyn --with-lpc10=dyn --with-ao=dyn --libdir='/usr/lib64' --mandir='/usr/man/'
Once your new version of SoX is compiled, install it using the upgradepkg command:
- If you built a newer version of SoX than the one that shipped with Slackware, then issue this command (where x.x is the newer version number)
# upgradepkg /tmp/sox-x.x*t?z
- If you built the same version of SoX as the one that shipped with Slackware, then issue the command:
# upgradepkg --reinstall /tmp/sox-x.x*t?z