I intend to use recordMyDesktop tool for screencasting on Linux. Its a good tool, but there is a limitation with respect to ubuntu. I cannot record a background music at the same time the voice is being recorded from the mic input.
In other words I need a mixer tool on ubuntu that can mix my mic-input plus a background-mp3 so that the combined input could be given to recordMyDesktop (since recordMyDesktop cannot handle mixing on its own). Do you know of any such audio-mixing on ubuntu that I can make use of ?