Hello! I have some major issues outputting from my Blackmagic Decklink 8K Pro. I’m sending key and fill to later be processes in Resolume but the video feed is delayed with between 3 to 4 seconds. If I disable the fill and only output one 8-bit channel the delay drops to 2-3 seconds which is still horrible. Everything updates in real-time in the editor as soon as I send my input.
I have tested sending NDI instead and that works perfectly with almost no delay. Same with outputting using Syphon Spout to OBS on the same machine. But due to reliability would I prefer to run the signal on SDI instead. And running an additional software like OBS to convert the Spout to SDI seems like an unnecessary step.
The machine is running an RTX A4000 with an i9-11900
UPDATE: This seems to be a bug introduced in version 2022.33910 released on 19 Jun, 2023. If I go back to any version before this everything works as intended.
Hello! I tested multiple versions to try to identify when the bug was introduced.
All versions I tested after 2022.32660 seem to have the bug. I think I specifically tested 2023.12000 and 2023.11510. And all version at and before works great.
Looking at the release notes I think this, from version 2022.33910, is the cause of the problem:
Hi! I have done some more digging this morning and found it’s related to me outputting key and fill at a high resolution. If I just output a fill the problem is still there but a lot smaller.
I setup a light weight test scene to measure the time. Outputting a timecode that is looped back into the same card.
Hey, can you tell me how your device is configured in the Blackmagic Desktop Video control panel. Can you also create a report from that app and post it here so I can see extra configuration information?
Thanks
Hey, I’m still confused why the changes to the build made things worse. However the report states that the card is only running at 2x PCIe speed. It’s an 8x card, can you try moving it to another slot to ensure it’s running at it’s required full speed?
Damn! Yes that fixed it for us. It was sitting in a 16x slot but for some reason this motherboard only has 4x on that slot (which gives us 2x with half the pins). Moving to another slot gave us the full 8x and the delay is gone.
But like you said, very strange that it works with older versions. Thank you for all your help!
