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

L. Lee llee040 at sbcglobal.net
Wed Feb 29 06:12:13 CET 2012

On 2/26/12 5:29 PM, "Mike Spreitzer" <mspreitz at us.ibm.com> wrote:

> 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.

QuickTime generally displays average, not designated frame rate. I don't
thing your sync problem is related to frame rate, either. Can you upload a
sample? Then we could try some stuff on it and give you some command
suggestions to try. Let us know what format you'd like for output, giving us
a couple of options, if that's acceptable.

Laine Lee

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