2020-22080-win10_GPU Direct Not Function Properly(Videodeviceout TOP)

Hello, We are trying to use the video device out TOP with Blackmagic Decklink to output an 8k 50p 8bit video signal.
We found that when we choose the GPU Direct, it seems not to function properly(the CPU cooking time is pretty high). But when we output 8k 50p 10bit video it seems fine. Here is some screengrab about 8bit v.s. 10bit output:


Could you check this for us? And if more information is needed, please let me know.

Our system spec:
-CPU: i9 9900k
-GPU: Quadro RTX 6000
-Blackmagic Decklink 8K in driver version 11.5

From what I gather GPU Direct is not supported on Blackmagic cards. AJA would be your better bet for that at this time, though I’m not sure if that would apply to outputs as well as inputs.

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Thanks for your advice. I do consider using AJA instead of Blackmagic, but the price is just way higher! But here comes the interesting part, from time to time I try to use GPU direct on Blackmagic, sometimes it work! but most of the time it doesn’t, so I consider it might just be some kind of bug I suppose.

TouchDesigner has support Blackmagic GPU Direct since the 2019.10000 series builds. Perhaps you could show us some screengrabs of your CPU / GPU usage before and after turning on the GPU Direct toggle?
GPU Direct mostly helps with frame latency, CPU work will not suddenly disappear. Can you report how much your frame latency improves with GPU Direct?

I highly recommend this tool for measuring frame latency

Thanks Ben, that’s good to know.

Wouldn’t this only give you the sum total of in and out latency though?