Pro Tools: 2 audio sources fall out of sync

Discussion in 'Mixing & Song Critique' started by SimonLoynes, Oct 18, 2005.

  1. SimonLoynes

    SimonLoynes Guest

    Hello there,

    I am a Pro Tools LE user and am trying to sych 2 sources of audio.
    Audio Source 1 is from a Mini Disk
    Audio Source 2 is from a DV camera (imported into Pro Tools via 'Import Audio from Movie' function)

    I can sync the audio at the beginning but within a few minutes it is way out, causing an audible delay. I have tried this with both PAL and NTSC DV tape audio sources and its seems to make no difference, they still fall out of sync. I dont really get why this would make any difference either as although the framerate is different, its obviously just a different way of representing one second. I am pretty stuckl at the moment. Its of concert footage about is approx 30 minutes long.

    Any ideas why this is happening?


    PS the audio from the DV camera syncs to the video (obviously).
  2. Dosser

    Dosser Active Member

    May 31, 2005
    Nashville, TN
    Your problem is that the DV Camera and the Mini disc have two different ideas of how to tell time.

    Both units use a crystal to define the passage of time, but they are obviously not synchronized with one another. Think of it as if we both had wrist watches and mine ran a bit faster than yours. If we set our watches the same, after a few minutes, they would be different.

    You can edit the audio to match the video. Every so often, you'd have to line up the sound to the picture again. As for lining up both sources of audio, it may be impossible. They are going to constantly drift apart, as you have already experienced. Even if you try to line them up every few seconds, they are going to really phase in and out with each other a lot. You can still line them up as best you can, and then use only one source or the other for your audio, instead of both.

    Next time, you need to make sure that all video and audio is recorded referencing the same clock reference, usually a video reference, with the recorders locked to SMPTE, usually running at time of day, with the same frame rate.

    I realize that's a little overkill, compared to using a minidisc, a consumer camera, and protools LE (which doesn't implement SMPTE), but that's how its done.
  3. kozzy

    kozzy Guest


    Chears dosser , I thought it was me going pear shaped on our last live recording, Problem now solved

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