FIXED: Frame Time Spikes due to Blackmagic Decklink Quad Hdmi Recorder

Bugs
1

On my machine, I found a reproducable problem with Blackmagic Decklink Quad Hdmi Recorder input, resulting in periodic spikes which increase and decrease:

ScreenshotSnip
ScreenshotSnip1775×997 142 KB

The Decklink is used with two inputs in 25fps. (No input is actually piped into the decklink card, but the behaviour also appears with videoinput)

The spikes appear alongside of a tiny gpu memory increase/decrease.(The two steps refer to the two decklink inputs).

Configuration:

  • Windows Tower
  • Blackmagic Decklink Quad Hdmi Recorder (installed Black Magic Video 14.2.1)
  • RTX4090
  • Intel i914900KF
  • Touchdesigner 2023.12000 running 25fps

Does this also happen on other machine and can this be fixxed?

3

I’ll take a look and see if I can reproduce the issue. The spikes are indeed likely due to the GPU memory reallocation that seems to be happening. Why it’s happening when the inputs arn’t active though is the question

4

I’ve been able to reproduce and I’m talking to Blackmagic about the best way to solve it.

1 Like
5

Thanks for checking!

6

Thanks for the report. I’ve improved this behavior for future builds. I think the change is too large to put into the 2023.10000 series Official though, so it’ll have to go into the 2023.30000+ series of builds