timecode Sync in video production, why Timecode isn't enough to stay in sync!

[henrirapp]

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A common misconception is that Timecode and Sync are the same thing, they are not, timecode is only a metadata identifier. Consider this common scenario that editors deal with regularly; On a production such as a comedy special, concert, or reality TV show, etc, you have multiple cameras and separate sound recording gear that records without cutting for long periods. You align all your audio and video files at their start points in your NLE software, but while it starts playing back in sync as you proceed down the timeline they slowly lose synchronization and by the end of the timeline it’s all gone wrong (often by several seconds in any direction). Even with timecode hardwired and aligned starts, how can they be noticeably out of sync by the end?

 

That’s because timecode doesn’t lock a camera or audio recorder’s clock to one another but acts as a metadata reference point for how to stamp the first frame when you start recording. Once you hit record on any device it relies on it’s own internal clock to govern frame rates and define what time is. Each device’s clock has small differences compared to one another, and over time these differences add up and are experienced in the form of drift. It might not be noticed on relatively short takes (like in the narrative world), but since it’s a cumulative effect any take that lasts 30-40 minutes or longer could start to noticeably lose sync. To prevent this scenario from occurring, every clock on set needs to be slaved to one central master clock source generating Timecode, Genlock, and Wordclock for everything.

 

 

Watch Full Video or read companion article at: https://henrirapp.com/sync-for-video-production/
 

 

[Philip Perkins]

Thanks.  There have been innumerable threads on this topic here over many many years.  The principle and the issue are not new.