Re: syncing audio and video... who's the boss?
Re: syncing audio and video... who's the boss?
- Subject: Re: syncing audio and video... who's the boss?
- From: "Chase" <email@hidden>
- Date: Fri, 27 Apr 2007 20:33:21 +0000
> THe answer to that question depends on what you are trying to do. For
> a video conferencing app, the answer is often that an external clock
> that is common between the participants in the conference is used to
> synchronize the media. For movie playback, it might be the audio, the
> video or an external clock depending on which media is more important
> to leave untouched or whether you need to synch to a video monitor or
> to some form of studio synch like black burst.
>
You are correct... I just found this page that answers the question precisely:
http://developer.apple.com/documentation/QuickTime/RM/MovieInternals/MTTimeSpace/index.html
"When an application opens a movie containing a sound track, QuickTime uses the sound clock as the movie master clock."
...
"In other words, if you play a movie containing audio and video media, the video will play at whatever rate the audio hardware is playing. If the movie lacks a sound track, QuickTime will use the system clock as the movie master clock."
Makes sense to me, since a slight sync adjustment of video would probably be less noticable to the eyes than a similar sync adjustment of audio would be to the ears.
- Chase
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