Live Production: Delay Audio to Match Multiview or Not?

I admit it, I’m a broken record on this topic. But I’m intensely curious about where the rest of you come down on this, especially you directors.

If this sounds like a techie-only issue let me assure you it is not. In a nutshell, the advent of huge LCD panels and multiview software has changed the game in live and live-to-tape production.

*The panels themselves can have 2-3 frames of built-in delay

*Multiviewer software lag varies from 5. to 1.5 frames

*Normal switcher delay is 1 frame

All told, there can be more than 5 frames of delay between when a picture is generated and when it actually plays out on the Program window of that giant LCD screen in front of you. A single frame of 29.97 video is 33.367ms, and 33 x 5=165ms. In the music world, a 165ms delay corresponds to a sixteenth-note pulse at a slow tempo (think In Your Eyes by Peter Gabriel). This is enough of a delay that if the audio isn’t delayed back to match the picture, there will be a noticeable sync issue.

The usual way this is dealt with is to put a ~160ms delay on the mix that feeds the control room so that the director and producers will see things in sync. I think this is a terrible idea, and I have five main reasons.

1. Directors compose shots by looking. Directors cut shows by listening. If the director is interacting with on-camera talent (putting up stills, rolling clips, cueing sound effects, etc.) and using a delayed audio feed, she is cutting the show 1/6 of a second later than when it is actually happening. This means everything goes up late. 1/6 of a second doesn’t sound like much, but when you’re cutting live comedy it can be an eternity.

2. If there is a live audience there is most likely a PA system. This has to be run delay free or the delay from the PA will come back through the mics and be heard on-air. As a consequence, when a stage manager keys his mic to the PL you will hear un-delayed audio bleed from the PA through his mic. This will drive anyone listening to both the stage manager and the control room speakers crazy.

3. If the control room shares a wall with the studio, the leakage can be a large issue. I have actually seen (and heard) this happen on a show. The show ended up abandoning the delay in the control room and learned to live happily with picture slightly out-of-sync, but audio in sync with the leakage.

4. Anyone who needs to monitor the director PL will hear the delayed program leaking through his or her headset. This effectively forces them to use the delayed audio as well. This sounds like a minor point, but if the mixer is forced to monitor the delayed feed, he or she will be more likely to upcut talent due to late fader moves.

5. The sync mismatch is NOT an audio problem, it is a video problem. If it can’t be fixed in the video domain it should be left alone.

Well, where do all of you come down on this? I have to admit I don’t see much consensus. I work on shows that use a delay in the control room, and shows that don’t. I much prefer the latter.


Peter Baird

REMOTE WEST 2018