No output from SDI ports 3 and 4 on Blackmagic Decklink Duo 2


I have a Blackmagic Decklink Duo 2. I have set its connector mapping to 4 individual ports using the Blackmagic Desktop Video Utility.

I can output from all 4 SDI ports using other software such as Blackmagic Media Express, but when I try to do the same from TouchDesigner Commercial the Video Device Out TOP lets me select from all 4 ports but only ports 1 and 2 successfully output to a monitor. There is no output from ports 3 or 4.

I am using the latest TouchDesigner Commercial official (2020.26630) with Blackmagic Desktop Video 11.6 drivers on a PC with Quadro RTX 4000.

Is there a way to fix this?

Thanks very much.

Problem area highlighted and an example toe file attached. There are 4 options in the drop-down: Decklink Duo (1), Decklink Duo (2), Decklink Duo (3) and Decklink Duo (4). Without changing any other settings outputs 1 and 2 work. 3 and 4 don’t.

SDI Out Test.toe (3.7 KB)

Worked it out. There is some sort of issue using TouchDesigner with the latest Blackmagic Desktop Video 11.6 drivers. I changed to 11.5.1 and all outs now work.

There was also a problem looping an SDI output back to an input on the same card and seeing it with the Video Device In TOP. With 11.6 drivers the Video Device In TOP starts rapidly alternating between a green screen and an error cross for a few seconds, then TouchDesigner crashes. With 11.5.1 it works fine.