operate on the first available sound track.
It so happens that I have such a .vob file on-disk, so let's see what ffmpeg thinks of it:
<code>
$ ffm... al.
{snipped}
Seems that stream 0 comes from film source: 25.00 (25025/1001) -> 25.00 (25/1)
Input #0,... the video stream. Stream #0.1 is the DTS-encoded sound track and #0.2 is its AC3-encoded Dolby 5:1 eq... alent. Stereo audio streams #0.3 through #0.5 are soundtracks with commentaries. Say I want to create
