Xvidcap-1.1.3-r1 does not compile audio capture support using the current ffmpeg-0.4.9 patch. Workaround is to use xvidcap's own internal ffmpeg tree with a new USE flag added called 'embedded-ffmpeg'. Using the new USE flag means the ffmpeg-0.4.9 patch must be disabled. Audio capture now works, but only from stdin & not from /dev/dsp (results in a blank audio track) .diff follows:
Created attachment 46933 [details, diff] xvidcap-1.1.3-r1.diff Diff to enable ffmpeg audio capture in xvidcap-1.1.3-r1
Does it works with latest snapshot of ffmpeg?
feel free to reopen if this is still an issue, please test with a more recent version before you do so.