I need to import to FCP some stock footage that came to me as an mpeg-1 file with the audio embedded in the video. I have tried a straight import but I lose the sound, I have tried a variety of options in Quicktime Pro with no luck. I have tried MpegStreamclip with no better success.
Actually, that process doesn't work because with mpeg-1 the audio is embedded and sort of invisible. But I now know that what you need to do is use Mpeg StreamClip to demux to mpeg2 with aiff audio. You end up with the 2 separate files - and m2v and an AIFF but at least I now can import the audio.
No, MPEG StreamClip will demux the audio and video automatically when exporting from MPEG-1 to QT. I have done this many a number of times and it has always worked. Maybe there is some issue with your file, but this does definitely work.