• Apple Final Cut Pro Legacy

  Audio drift problem

  Posted by Patricia Burgess on June 27, 2008 at 10:32 pm

  I am trying to sync footage of dancers dancing to a track up to the very same track in fcp. However I am getting audio drift of about 10 frames by the end of every song (so the beginning starts out synched up, then the end is somewhere between 5-10 frames different). I was the one who shot some of the footage, so I can tell you the following:

  Footage was shot at 60i (29.97 fps), was captured into FCP at 29.97 fps, and is in a sequence set to 29.97 fps. The audio is 16-bit stereo, 44.1 kHz.

  I have done this three times before and it has worked fine (same exact settings on the camera, on the logging and on the sequence).

  Any ideas what could cause sudden audio drift like this? The track the dancers are shot dancing to is the exact same track I’m using in fcp, everything should pretty easily match up, so I’m really baffled.

  Colin Mcquillan replied 18 years, 2 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Colin Mcquillan

  June 27, 2008 at 10:50 pm

  Your FCP timeline, is it 44.1K or 48K? I would imagine 48 as this is what FCP likes best.

  Try converting the 16bit 44.1K audio track to a 16bit 48K .aif before importing it into FCP. Use i-tunes for this (in itunes advanced menu/import options select 16bit 48K .aif as import method/format, bring in the original track to your library, right click on it and choose “convert selection to aif”

  Colin McQuillan
  Van. B.C.
• 

  Patricia Burgess

  June 30, 2008 at 2:44 pm

  Hey Colin, and thanks for the help. The track was originally a 16-bit, 44.1k aiff. I did what you suggested and converted it to 16-bit, 48k aif in iTunes, however it’s done nothing to fix the drift (the song still starts off synched then ends up about 5 frames off, which can be heard). What else could it be, perhaps?

  Thanks for your time.
• 

  Colin Mcquillan

  June 30, 2008 at 7:43 pm

  Hum.. I’m still convinced it is the 44.1K vs 48K causing your problem. The 44.1K frequency is perhaps being sped up ever so slightly to increase its frequency to 48K causing it to shorten ever so slightly over time.

  Try changing your timeline in FCP to 44.1K. Click somewhere in your timeline (anywhere, so the timeline box is active.) From the sequence drop down choose ‘Settings’, and choose 44.1K. Now delete the audio track from the sequence, then replace it, so it’s freshly inserted into the timeline.

  Colin McQuillan
  Van. B.C.

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