NVIDIA Upscaler flickers when switching inputs with different pixel formats

Bugs
1

Hi.

I encountered an issue where the NVIDIA Upscaler flickers when the input source is switched under the following conditions:

  • A Switch TOP with “Blend Between Inputs” turned ON is connected as the input to the NVIDIA Upscaler.

  • The Switch TOP has two connected nodes:

    • One with 32-bit fixed (RGBA) pixel format

    • One with 8-bit fixed (RGBA) pixel format

  • When the Switch TOP changes its index to switch the input, the output of the NVIDIA Upscaler flickers.

As shown in the attached video, the flicker occurs specifically when the index switches to 1.

844f74d70857c0fbe3a7b849adebc3ea

Here is the project file that reproduces the issue.

nvidia-upscaler-report.toe (5.0 KB)

Environment

  • TouchDesigner Version: 2025.31550

  • OS: Windows 11

  • GPU: NVIDIA GeForce RTX 5090

Thanks.

2

Thanks for the example. I suspect the issue is because the upscaling model is running in a separate thread and there is a delay between when the format change is made and the new output is available.

We have discussed internally adding a mode that would force the node to wait for the output to be ready, but it’s not on our current timetable.

That said, switching the format like this may not actually be very efficient. I believe the AI model that Nvidia is using here only accepts 8 bit images, so internally we need to convert the 32 bit image back to 8 bit for the model and then convert the model output back to 32 bit.

1 Like
3

Hi robmc,

Thank you, that explanation was very helpful for my understanding.

I’ll consider providing both inputs as 8-bit.