• Apple Final Cut Pro Legacy

  Audio drifts over time

  Posted by Victor Kohler on September 4, 2008 at 3:24 pm

  Hi,

  im having an issue with audio drifting over time. At the beginning of my sequence the audio syncs up with the waveform but later what i hear and what i see in the waveform is totaly different.
  The audio im using is from the composers and bounced from Apple Logic.

  Im editing in Apple Prores HQ with 48 kHz audio converted from 44.1 kHz in an 48 kHz sequence. The project is quite big and im working with multiple projects and sequences open. I tried reconecting the audio but that doesnt work. Any idea what causes this problem?

  My system is a Mac Pro 2 x 2,66 GHz Dual Core Intel Xeon with 12 GB RAM
  Black Magic HD Extreme

  Im working from two internal and two external drives. Both my audiofiles and my projectfiles are on my internal ones. The material is spread out over all four drives.

  Jeremy Garchow replied 17 years, 8 months ago 4 Members · 3 Replies
• 3 Replies

• 

  Rob Forsythe

  September 4, 2008 at 4:20 pm

  If you correctly converted the 44 kHz files to 48 kHz files,
  then I’d suspect a timing problem in the original files that were supplied to you.
• 

  Steven Gonzales

  September 4, 2008 at 8:23 pm

  I’d try taking one of your original 44.1 kHz files, and open it with Quicktime, then export as 48 kHz (converting there instead of an FCP sequence), and see if syncing that to it’s video makes a difference with drift.

  Also check the bit rate of the originals (how many bits are in the audio samples, usually 16 or 24) and see if that remained consistent throughout the workflow.
• 

  Jeremy Garchow

  September 6, 2008 at 9:56 pm

  Sounds like a media organization problem to me.

  Try a mixdown of your sequence (select all (command-a) then hit option-command-r).

  This will essentially render all of your misconstrued audio into one, temporary concise file for playback.

  See if it plays in sync after that.

  Jeremy

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