mimoLive SDI playout freezing (BM TV Studio HD and Ultrastrudio HD Mini)

I’m cross-posting this from the black magic forum, and it’s related to my other thread about mimoLive and outputting key/fill on a decklink duo. In that thread I’m trying to get SDI playout working on the decklink because of the problem I’m going to describe in this thread.

I have a TV Studio HD receiving input from mimoLive running on a Macbook Pro. MimoLive outputs fill and key signals on SDI A and B out on an Ultrastudio HD Mini into two of the SDI input channels on the TVS. I have Upstream Key 1 (on TVS) set to Luma with Fill set to the SDI A signal and Key set to the SDI B signal from the Mac.

Setting the Upstream key to ONAIR works as expected - graphics output from mimoLive is superimposed over the image from the current active camera (on Program output).

My problem is that after a period of time (sometimes as little as 5 minutes, sometimes as long as 20 minutes) the Fill/Key signal on the TVS freezes/stops working. If a lower third is active when this happens, for example, the lower third remains on screen. If no graphics are active, trying to play something like a lower third doesn’t appear at all on the TVS.

To recover, I have to restart mimoLive on the Mac. (Note: graphics do not freeze in mimoLive, they continue behaving as normal in the preview window etc).

Initially I thought this might be a frame rate issue, but I have the identical frame rate set on all components - TVS is set to 1080p59.94, as is the mimoLive document, the SDI playout configuration in mimoLive and the output on the Ultrastudio HD Mini.

I’m at a bit of a loss as to how to troubleshoot this. I’m currently trying to get the decklink duo working for SDI playout to see if the problem also occurs with that hardware device, but other than that I’m stumped. I have posted a thread on the Black Magic forums to see if other graphics engines like CasparCG have exhibited this behaviour. Any ideas for troubleshooting or fixing would be appreciated.

A response from the black magic forum provides a clue:

Based on your description it sounds like your CG is freezing the output to the Decklink card. There is a setting in the Decklink control panel to freeze on last frame. If that is selected and your CG loses communication with the card, it is possible it will just freeze until such a time as you reboot your CG and re-initialize the card.

Unlikely to be an ATEM issue as I don’t believe there are many failure states that would allow a full input to freeze like that. I suppose it is possible that it is a frame-sync issue but again highly unlikely.

I will change the BM card not to freeze on last frame and see what that does, but if this person is right how do I go about finding out why mimoLive loses connection?

I have changed my BM US HD Mini to Single link mode, and changed the ATEM Key config to use pre multipied key… so far I’ve been able to run the SDI playout for an hour without the freeze frame issue.

Ran an overnight test, SDI playout on a single channel to ATEM with Pre Multiplied Key, and it successfully played for about 8 hours without issue. I’ll take some screenshots of the configuration and post so that future folk don’t run into the same issue.

I have no idea what has changed but fired everything up tonight, and I’m back to staring at a frozen frame after “going live”.

I’ve posted a video of the issue here: https://youtu.be/IuBrAMehx74

Can anyone spot the issue with how I have set up everything?

As an old beta tester and being tried every single mimolive version in order to get my setup running in the best way, I would suggest you that go back and try earlier versions