You can still use
ffmpeg from FFmpeg if you prefer (like I do). You have two main choices, and a PPA:
Download a static build of
This is easy and supports MP3 encoding. Just go to the FFmpeg Download page and get one of the "Linux Static Builds". Or if you're lazy:
tar xzvf ffmpeg.static.32bit.latest.tar.gz
Then execute the binary:
./ffmpeg -i input ...
Another option is to compile. It takes more time, but allows you to fully customize your build. See Compile FFmpeg on Ubuntu, Debian, or Mint.
See Ubuntu Multimedia for Trusty.
Example command for MP3 encoding
ffmpeg -i input -codec:a libmp3lame -q:a 4 output.mp3
Example command for stream copy
If your flv input already contains MP3 audio (
ffmpeg will tell you), then you can simply re-mux instead of re-encode:
ffmpeg -i input -codec:a copy -map 0:a output.mp3