[MEncoder-users] Questions about fps and synch for vintage QuickTime movies

[Mike Spreitzer]

I am retiring some old computer equipment, and want to transcode some old 
QuickTime movies into a modern format.  These movies were found on 
removable media with dates in the spring of 1996.  I think they were made 
on my PowerMac 7500/100, on those dates or not many years before.  That 
would be with System 7.5.something.  I think I made them using some 
standard recording software of such Macs.  I think the video source was a 
S-VHS camcorder, connected to the Mac via a S-video cable; the audio came 
in through the Mac's microphone or an external microphone.  In Mac 
filesystem terms, these movies have type/creator of MooV/ttxt.  Each has a 
small resource fork, containing just one resource (of type MooV), and a 
large data fork.

I have copied these files to modern systems, losing the resource fork 
along the way.  I can play them with mplayer and QuickTime 7 on Windows 
Vista and MacOS 10.6 (also the current QuickTime on MacOS 10).  Oddly, 
mplayer and QuickTime disagree about the frame rate.  I will discuss one 
example movie.  On both MacOS 10 and Windows Vista, QuickTime 7's 
inspector says the movie's frame rate is 27.16.  On both MacOS 10 and 
Windows Vista, mplayer says the movie's frame rate is 30.00.  In all four 
cases, when I play the move the sound and video are in sync.  I used a 
stopwatch to time the playback time between two events in the movie (it is 
short), and got the same amount (33 seconds) in each of those four cases. 
Why are these two pieces of software making different claims about FPS?

When I try to transcode, using mencode, the sound and video get out of 
sync.  I am guessing that understanding what is going on with the source 
will help.

Thanks,
Mike