Having too slow system to actually play the resulting clip? Sound stuttering would suggest that...
Certainly not. If i download an original mpg movie from the net and try to view it, the sync is perfect even if i get some frame skipping.
With MPGs produced by me using Mencoder or FFmpeg, the sync is horrible and there are no frame skipping whatsoever. Even under high CPU load i get 0 skipped frames!! I'm not sure but perhaps this is what is causing the problem?
Or does the generated clip have audio sync issues with Linux/Windoze/Mac OS X aswell?
Most likely, because i tried to produce a VCD compliant mpg and produced a VideoCD out of it. When i tried to play it with my stand-alone DVD player, it had the same problems. So, it's not OS or hardware related.