Playout Delay

I’m testing out a number of different setups here in the studio. Currently, I have an ATEM 2 M/E Production Studio 4K, with it’s ‘program out’ going into the input of an UltraStudio 4K Extreme, which is feeding mimoLive via Thunderbolt. I’m playing out ‘program’ from mimoLive back to the UltraStudio, which works fine except there is a two second delay between mimoLive and the UltraStudio. A few frames delay would be OK, but two seconds is not going to fly in a live scenario. Any ideas on why I’m seeing this delay?

I went into Preferences and changed the Audio Buffer Samples from 512 to 128 and that dramatically reduced the latency of the outgoing video. Very usable now!

Well, I found that after a while the latency came back. I went in to the preferences again to play with the Audio Buffer setting, but that crashed mimoLive.

@“Jason Jenkins” I am guessing you are referring only to the audio part of your playout that gets delayed and the issue at hand is a sync offset between audio and video. Otherwise, changing the Audio Buffer Size shouldn’t have any impact on the video part.

Following that guess, this sounds like a potential bug in mimoLive, and I’d like you to check a few more things in order to find its epicenter:

  • In your video source, is there a delay time set in the Audio Device settings? The settings panel pops up when you click the cogwheel at the right from the audio device popup menu.
  • Does the delay disappear when re-selecting audio and/or video devices in the video source?
  • Does the delay disappear when selecting other audio and/or video devices in the same video source?
  • Does the delay affect other input sources using the same device?
  • Does the delay affect other input sources using different devices?
  • Is the delay introduced instantly or does it built up over time?
  • Is the delay audible over the monitoring device?
  • Is the delay audible in a simultaneous recording or live stream?
  • Is this 100% reproducible or does it occur randomly?

Sorry for that many questions. Your answers will help a lot in identifying the cause of your issue.

EDIT: Also, what version of mimoLive are you using?

Hi, Beni:

It’s actually the video that is delayed. I’m not listening to audio in my testing. It is strange that the audio buffer is affecting the video. Perhaps it is just coincidence––I just changed the audio buffer again and it did not effect the video delay.

The video delay varies from time to time and does not seem to be constant. When I hooked up my Macbook Pro this morning, the video delay is nearly 3 seconds from the mimoLive interface to the UltraStudio 4K program out. I tried switching to the Facetime camera on my Macbook Pro and the video delay was still evident.

My Macbook Pro is a 2011 model–

@“Jason Jenkins” That’s something different then. Could you provide us with a process sample of mimoLive when that happens? To create one, open Applications > Utilities > Activity Monitor, make sure the CPU tab is selected, select mimoLive from the list and then click Sample Process either from the menu that appears when you click the gear icon on top or from the View menu. Send me a message of that.

Does audio stay in sync with video, i.e. does it have the same delay?
Do you see the same delay in other applications like Blackmagic Media Express?

Well, yesterday in my testing I was not able to reproduce the delay, so until I do I won’t be able to provide a process sample. I’m hoping it doesn’t happen again!

@“Jason Jenkins” The issue might be related to CPU load. It is quite possible the delay only happens when your machine is under a bit of stress.