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5D Mark II audio sync issue or problem.

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    5D Mark II audio sync issue or problem.

    Last Wednesday I used my two 5D MkII's in a 3 camera music video shoot. The third camera was a Sony PMW-EX1. Audio was recorded on two additional devices. One audio recording device was an Edirol R4 Pro. The other audio recording setup was a Tascam USB Interface to a MacBook Pro.

    The Sony Camera, Edirol, and Tascam/MacBook Pro devices all synced sound perfectly over the full duration of the shoot (just over 20 minutes). To clarify - once the different sources are sync'd quickly and easily to the slate clap on the waveform at the beginning of the shoot they all stayed perfectly in sync for the rest of the video.

    Both Canon cameras audio and video sync'd perfectly to each other but drifted significantly from the other 3 devices even over a 3 minute segment. That is a very serious problem for me and one that introduces significant post-production trouble and expense.

    This issue was so unexpected (I haven't run into this in years of working with a range of equipment) that I performed 3 subsequent tests to confirm that the 5D MkII's run too fast. The results from the tests show both of my 5D Mark II's run about 14 frames too fast in 10 minutes. Audio that is 1 full frame out of sync is noticeable on sharp sounds causing an echo. Audio that is 2 or 3 frames out of sync causes echo on any sound and looks odd in terms of lip sync.

    That the two Canon cameras audio sync'd OK to each other tells me that the cameras can be calibrated to a standard. Evidently they are just calibrated to an incorrect standard.

    Anybody else experience this? Does anybody really know if this is likely a chip issue or a firmware issue? Does anyone know an easy, reliable way to get the clips to conform to the standard without time-consuming constant tweaking?

    I contacted Canon tech support and the girl there wasn't too concerned. She said: There is no fix and that the 5d isn't really a video camera so what did I expect? Nice!

    #2
    I'm guessing you set your project to 29.97fps but the 5Dm2 actually records true 30fps. That would explain the slow drift. Try taking the same clip and use cinematools to conform the clip to 29.97 and then try again.
    Hunter Hampton
    hunterismyfriend.com
    vimeo.com/hunter

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      #3
      The 29.97 vs. 30 fps might have something to do with it, but as far as I know, unless you are fully synced with timecode jammed, it's possible for almost any two recorders to drift from each other over extended periods of time. The fact that you haven't had that problem in the past, at least for 60+ minute clips, is more luck than anything else isn't it? If the recorders aren't running off the same clock, then there's a godd chance that they will drift over extended periods.

      Anyway, this usually can be easily corrected in post depending on your NLE. Just sync to the slate like normal, and then stretch or compress one audio track (with pitch correction) until the ends/tails stay synced -- for music, if you have a wild track, I tend to stretch/compress the wild track so as not to mess with the video track/frames. Since you're talking only a few frames of stretch/compress over an hour of time, it will be inaudible.
      BayTaper.com | One man's multimedia journey through the San Francisco live jazz and creative music scene.

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        #4
        Hey Michael,

        I'm just wondering if you resolve your problem because I have the same trouble now ?
        Thank you for helping !
        Marc

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          #5
          With the latest firmware 5D shoots 29.97 in NTSC land

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            #6
            Originally posted by icimarc View Post
            Hey Michael,

            I'm just wondering if you resolve your problem because I have the same trouble now ?
            Thank you for helping !
            Marc
            There could be a couple of reasons for this problem. When the thread was originally started, there was no 24p, true 30p so sound sync was a problem for everyone. Nowadays, if you're still having audio problems and are shooting with current firmware, then your sampling rate might not match. I had to resolve a similar issue with a music video where the recorded song for use in the final video was 48khz but the performance music was something like 44.1 or whatever. In any case, I had to speed up the 48khz song just a tad. Ran it at 99.9% of original duration and it worked out fine.

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