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Trouble syncing two different audio sources.
Hi, I’m using the newest version of Premiere CC and am having issues combining a separate audio source to camera audio. The camera is recording AVCHD 1080p with 48000kbps (compressed) audio. We are combining the camera audio with a separate microphone feed from a speaker’s lavalier microphone. This audio is also recorded at 48000kbps but in AIFF format.
In premiere, all goes well when matching up the two sources in the beginning, but the two gradually separate from each other as the timeline moves on. For a 3 hour event by the end of the timeline, the two sources are almost a full second out of sync. What could be causing this?
At first we thought it was because of a different sample rate, but the same thing happened when we matched rates. Could it be a compression issue? Any advice is greatly appreciated.Thanks!
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3 Replies
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Hi Matt,
Video cameras have very precise timing since there can be no variance when playing back video – the frame rate can NOT be “off a little”. The same cannot be said for small, inexpensive audio recorders and that is most likely the issue you’ve run into.
All I can suggest is every so often, use the Razor to cut the audio clip and then shift it over as needed to maintain sync with the video clip audio.
Note that if you change the timeline display to “Show Audio Units”, you can then adjust the audio down the sample rate, rather than being limited to the video frame rate of 1/30 second for example – at that “resolution”, you may never be able to exactly match the two waveforms and that doesn’t sound quite right.
With Audio Units selected, you can zoom in down to the individual sample to precisely align the two audio clips.
I’ll do that to tweak audio sync, then set it back to normal video frames time display again to continue editing.
Hope this resolves your issue
Thanks
Jeff Pulera
Safe Harbor Computers -
Hey Jeff,
Thanks for your advice. What kind of equipment would you recommend to get the precision required to have syncable audio from a separate feed? We have the wireless lav receiver going into an m-audio interface fed into Audition. I thought this would have sufficed. We also have a zoom recorder with xlr inputs we could use. This is unfortunate because we have so many events like this that require both camera audio and a separate feed, and having to razor and nudge a lot is very time consuming. -
Just shot 6 dance recitals, 2.5 hours each, with two cameras. One camera was AVCHD, the other HDV feeding into an Atomos Ninja 2. The two clips sync up perfectly in Premiere and maintain that sync to the end. I’ve never experienced that with non-video camera audio recordings, there is always some degree of drift over time when trying to sync to video.
Jeff Pulera
Safe Harbor Computers
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