Silly me!
I used JMF to record from a webcam, and saved the video as mjpg and the audio as linear in what I think is a .mov file. (Yes I can do that - can't do sensible things in java but that is ok)
I am about to use JMF to write a converter - if I can ever get Java to believe in mpeg ...
Perhaps though - I have seen some references to doing it but ... VLC can be used to suck out the mjpg and stream that to something, also run VLC "force(ing) demultiplexer and decoder" (whatever that means) to recognize the linear audio, and stream that into the same something and save it as mpeg-1 and mpega in a .mpg file.
Any help appreciated
Petr