Radio jockey 0.0.1
The Internet radio broadcaster
Radio jockey is free software distributed under the GPL, it works well with all of your sound applications on your Linux computer, and it uses the powerful GStreamer multimedia framework (made by Fluendo) and PulseAudio sound server.
What it does
In layman's terms, Radio jockey:
1. records sound from your applications, line inputs and microphones,
2. shows you the peak and RMS levels of each channel,
3. mixes these recordings, in real-time,
4. plays the mix back into a sound output of your computer (if you want to),
5. encodes the mix into MP3, and
6. sends it to your SHOUTcast or Icecast Internet radio server.
How it works
Modern Linux distributions route sound into PulseAudio, which does the dirty work of routing each application's sound into the correct output. PulseAudio is also nice enough to provide a "monitor input" for each output, and this is precisely the feature Radio jockey uses to record real-time sound, in addition to the regular microphone and line-level inputs.
When you're broadcasting with Radio jockey, the PulseAudio volume control comes in very handy. Use it as a switching board to move applications among outputs and control their playback volumes, so you always get the mix you want. Additionally, you can set up your PulseAudio server to provide any number of "virtual outputs" you can plug your applications into, so your radio never runs out of sound.