[Chris Todd]

This is an interesting issue. I had a weird version of it yesterday. I had recorded HD video at 23.98fps with accompanying 48kHz audio from the camera mic. I also recorded audio separately at 48kHz. (.WAV) The two should sync up perfectly, right? Well I bring both versions of the sound into an FCP timeline and the sync drifts out.

OK so bring the same elements into (trusted) ProTools and hey presto the two versions of the sound sync up perfectly!

Wot is the haps?

Check the sample rate stamp on both versions and they both tell me 48kHz.

Hmm… If I export the separate audio from protools with sample rate conversion to 48.048 (0.1% pull up) and import that into FCP, It synchronizes in the timeline. (I did a quick QT export and the output stays in sync too!)

What does this tell me? If the video is running at camera speed 23.98fps then any sync sound running at capture sample rate should be exactly in sync. It IS in PT; it ISN’T in FCP. Therefore it would seem logical that FCP is running an automatic pull up on the QT picture/audio file OR is applying a pull down to the separate .WAV audio file. Either way my brain is now on fire… but after my SRC on the .WAV material I can now proceed… It’s not ideal.

If anyone can shed further light on this I’d be grateful.

CTPP