Blackmagic output in new editor


i’m trying to get a clean output from U4.26 or UE4.27 while playing the level. I’m using a blackmagic decklink 8k. In the quickstart guide, it is mention that it is possible to output in the play in new Editor view PIE if the viewport resolution matches the output resolution.

I’ve changed the output in the Advanced settings of the viewport with the screen scale percentage to 100. In addition I tried to use an Execute Console Command with “r.SetRes 1920x1080” wich does’nt seem to change anything.

I don’t have any error messages on the output log but the capture doesn’t update.

Does anyone succeded to use the blackmagic output in play ?

I just want to have a clean output while playing. I’ve tried NDI in the past, but the NDI cameras are conflicting with my system.

Thank you !