回複：軟件轉格式的話，理論可行，實際上我很少用。

I use Prism (video) and its Switch (audio) converters all the time. Basically, they can convert:
* rm -> mp3
* mp3 -> mp3
* flv -> avi
* rmvb -> avi
* avi -> mp3
* vlc -> mp3
etc.

But most of time, I need convert other formats to mp3, and convert mp3 from high bit rate to 128bit (which I perfer).