Comment 18 for bug 207406

from a quick glance, I don't think the problem is in ffmpeg, but in avidemux.

avidemux tries to load the codec for mp3. ffmpeg does not have mp3 support built-in, but uses lame. lame support is only available in libavcodec-unstripped-51 in multiverse, not in main.

the correct fix is to add a check for null in avidemux and report a "codec not found" to the user instead of relying that lame is available.