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Audio / video out of sync

I'm using Screenflow 9.0.3 on a Mac mini with OS 10.15.5

I'm capturing video from a Canon DSLR, via HDMI out to a Mirabox HD USB 3.0 HSV325 Capture Box, connected USB-C direct to the Mac

I'm capturing audio from a Blue Yeti microphone via the USB3 hub in my Dell monitor, to the USBA port on the Mac.

The camera is setup for 1080P 29.97fps NTSC output. I am capturing at 30fps in Screenflow.  After some troubleshooting, this seemed to get me the most reliable frame rate with one unique image on every frame in the timeline.

But my audio is roughly 5-6 frames ahead of my video. This seems to stay constant eg both capture at the same speed. Though I have not done a test longer than ~30 seconds.

I've tried uninstalling the Telestream driver and not capturing desktop audio and/or video but it doesn't seem to help. 

Any ideas? Thanks 

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 2 yrs ago
    • Reported - view
    Steve Kirby said:
    But my audio is roughly 5-6 frames ahead of my video.

     When using separate devices for video and audio they may be offset because they are different signal paths. Ideally, you'd want your audio to go through your camera.

    The Telestream audio driver is specific to capturing computer system sound and has no impact on audio coming in through USB devices.

    It's possible that you could make a feature request to allow you to enter a delay offset to account for the different latency in the different signal paths.

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  • CraigS Thanks Craig.  So this is unlikely to be anything to do with sample rates? Since the mic is USB output, not analogue, I don't think there is anyway I can get it's signal in to the camera.

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 2 yrs ago
    • Reported - view

    Steve Kirby Sample rate generally would drift rather than be a constant offset.
    If the mic has a sample rate control though you could see if you can change that to see if it has an impact.


    Audio into the camera would require a mic compatible with the camera's mic jack.

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  • Some people have recommended using the Apple AUSampleDelay filter, which would probably work except that it seems to be limited to a max value of 4410, even though you can enter higher numbers in the textfield.

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 2 yrs ago
    • Reported - view

    Steve Kirby You could just shift the audio the needed 5 or 6 frames. If it comes as one clip with the video, you can detach it and move it by hand. A hand clap can give you a distinct sync point if needed.

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  • 2 yrs agoLast active
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