Audio out of sync

Warthog

Warthog

Active member
I am experiencing a weird issue with FCP X. For some reasons, the audio and video are out of sync by as much as 14 frames. An example can be seen here: http://vimeo.com/30794696 at around 0:47.

This particular clip was shot using iPhone 4 (720p). However, I have experienced exactly the same problem last summer with my DVX100B (and thought it was a camera issue at first): http://vimeo.com/26285341 around 3:02 or here: http://vimeo.com/26911172 at around 0:40

The original clips are playing back fine, but as soon as I import them into FCP X, they are off (even before I drop them onto the timeline). It would appear that this only occurs in clips with short cracking sounds, but I am not 100% - it could be that it is just much easier to spot this in these clips.
 
Are you importing directly from the device, or through some intermediary?
Are you Optimizing when you import?
 
iPhone was directly from device, for DVX100B I tried both - directly over FireWire and then from a .dv file captured by iMovie. No optimization, no proxy media, just the analyzes for color, people and camera shake (I have also tried to turn all this off, but no change).

And just one more thing: the DVX footage was captured on Mac Pro quad core 2GHz, 8 GB RAM, the iPhone footage on an 2,4 GHz i5 MacBook Pro with 4 GB RAM.
 
Usually this is caused by a mis-match of audio sampling rates. The video clips should have audio of 16-bit, 48kHz. Open the original clips into QT Player, Cmd+i for the Inspector window, verify the audio was recorded this way.
 
Hm... DVX footage is normal 48 kHz stereo, iPhone stuff 44 100 Hz mono.

I could understand mismatch between the timeline/sequence settings and the clip actual properties. But this occurs already in the viewer/browser before there is any sequence setting to speak of :-( :-O
 
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