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Activity Forums Apple Final Cut Pro FCPX – tiny sync drift, with very long shots

  • FCPX – tiny sync drift, with very long shots

    Posted by Karl Fayeton on February 6, 2017 at 5:38 pm

    Hi everyone,
    I’m a teacher and I’m recording my lessons so my students can watch them later.

    I have :
    – 1. Video (master) : my iPhone 6S that is recording the whole scene ;
    – 2. Video : I record my Macbook screen with OpenBroadcaster Studio ;
    – 3. Audio : a Rode smartlav+ mic to record my voice.

    Everything is set on 1080p 30fps.

    But the projects are VERY LONG : 3-5 hours straight, captured in one shot.

    I have a sync issue :
    it seems like the screen recording and the audio mic are drifting from the iPhone main video footage, by 3 frames (100ms) per hour exactly.

    It is very annoying to split the files afterward to sync it back, because 100ms per hour means it’s impossible to adjust speed directly in Final Cut, because the software doesn’t take “99.99%” as a valid speed correction.

    Is there a way to avoid this tiny sync drift ?

    I imagine a solution where I can put a marker in sync on a first clapper at the beginning of the recording, and another marker in sync at the end of the recording, and Final Cut will match the beginning markers and the end markers.

    Is there anyone with similar problems, and solutions ?

    Thank you. Sorry for my bad english, I’m not a native speaker 🙂

    Karl Fayeton replied 9 years, 7 months ago 3 Members · 5 Replies
  • 5 Replies
  • Noah Kadner

    February 6, 2017 at 7:32 pm

    Nope and this is precisely why folks spend extra money on pro-level cameras and timecode equipment. Consumer gear can and will drift, especially over very long takes. But if that’s not in your budget, he only solution is to blade and manually resync to counter the drift.

    I suggest starting from about an hour away from the end and see how many times you need to blade again as you approach the start of the take where sync will be closest.

    Noah

    FCPWORKS – FCPX Workflow
    FCP Exchange – FCPX Workshops
    XinTwo – FCPX Training

  • Karl Fayeton

    February 6, 2017 at 8:42 pm

    Oh, okay :-/
    That’s unfortunate… but I will live with it.

    I tried my “two markers” technique and I discovered that I can stretch the shot very precisely with the Speed bar, so that will do it for now.

    Thank you for your quick answer 🙂

  • Joe Marler

    February 6, 2017 at 10:48 pm

    Another solution is to sync it with PluralEyes, which does continuous correction for sync drift over the entire take: https://www.redgiant.com/products/pluraleyes/

  • Karl Fayeton

    February 7, 2017 at 5:26 am

    Yeah I tried it, but the sync was not perfect, so why spend hundreds of dollars for a long automated process that I need to manually correct afterwards ^^

  • Karl Fayeton

    February 7, 2017 at 5:28 am

    If I had 12 mics and 4 cams, maybe PluralEyes would totally worth it 😉

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