ATEM Audio/Video not Sync

Questions about ATEM Switchers, Camera Converter and everything live!
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Ming Hui

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  • Joined: Sat Feb 23, 2013 3:37 am

ATEM Audio/Video not Sync

PostMon Nov 25, 2013 3:29 am

Hallo,
I'am using ATEM 1 M/E and typically used for live event using projector and LED TV.
I see the video at projector is not sync with the audio out put from speaker. Would seem obvious at the time of the speech or singing. How does the solution. Sometime i used sony EX1R and Panasonic AC130 with HDMI-SDI converter. Thank you
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Thomas Seewald

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Re: ATEM Audio/Video not Sync

PostMon Nov 25, 2013 11:01 am

ATEMs Output is "in sync" ! (Max 1 Frame video delay - normally invisible). I don't know the delay in HDMI-SDI-converter, maybe 1 Frame. Some cameras have also delay on their outputs. The rest of the video delay comes from your projector.

So you'll get "audio before video". To reduce projectors delay, try to find one, which have the same native (!) resolution as your ATEM output is set to. But this have no effect to delay caused at ATEMs input.

A professional camera with genlock und SDI outputs would help, minimizing delay at ATEM input.

If you don't use the ATEM audio mixer, you can use an audio-delay on input (maybe from Behringer). Sometimes, you'll need a delay up to 5 frames.... (Only care about delay to output, not at projector)

This only works, for recording or live broadcasting.

For a live event, where you can see the live actor and the video at the same time, you can go two ways:

1.) Delay audio. For the audience, projector-video and audio seams to be in sync, but when looking to the actor directly, there will be a delay "video" before audio. Also a singer could be very confused, hearing himself e.g. 1/5 second later....

2.) Do nothing to delay the audio.

Don't forget, that you'll get a audio delay of 1 Frame every 14m distance from the stage... ("slow" sound velocity vs. "fast" light velocity)

So try to find the best compromise ....
thos-berlin - Thomas S e e w a l d
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Chad

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Re: ATEM Audio/Video not Sync

PostMon Nov 25, 2013 8:09 pm

The delay is most likely happening in the projector itself. I came into a place that was running their video at 1080i, but the projectors native resolution was 1280x800, and the projector was adding 4 frames of delay. Once I switched them over to 720p (1280x720), the projector no longer needed to resize the image and it's delay went away.

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