Hello,

I've been using vMix for a few years to record four simultaneous files from two Desktop captures of two screens, while displaying the fullscreen to a fourth monitor.
In the last week, I've started to see what appears to me to be screen capture artifacts in my vMix Output window and resulting downstream files, and fullscreen External output. See attached screenshots.

The artifact "blip" occurs randomly, maybe 10-12 times over a multi hour zoom call. Note I do not see the "blip" happen on the source screen, or the zoom video call.

Any troubleshooting thoughts are greatly appreciated.

Some observations:
The artifacts appear when recording, or even when idle.
vMix stats average around: Render time: 12 GPU Mem 17 CPU vMix 18 CPU Total 24
Minimal software installed and running. virus sw is Windows Defender, Chrome browser is NOT running.
Note the time stamp overlay remains visible when this happens.
Windows, Dell and NVidia drivers are up to date.

Specs:
vMix 4k 24.0.0.72 x64
Dell 8940 Desktop
CPU: i7-10700 4.8GHz
RAM: 16GB
Disk:1TB M.2 PCIe NVME SSD
GPU: Nvidia Quardro RTX 4000 8GB
OS: Win 10 Pro

Screen resolutions
vMix app screen: Res 3840x2160
Capture screen 1: Res 3840x2160
Capture screen 2: Res 1920x1080
Fullscreen external output: Res 1920x1080




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I suspect that you're suffering a bandwidth issue with respect to the GPU. Both feeding and capturing those screens, at those resolutions/frame rates) is a lot of workload.

First, I'd reduce the resolution of screen capture #1 to 1080p.

If that's not enough, suggest a hardware approach to screen capture. Offloads much of the burden from the GPU.

I have may have corrected this issue. I recalled that a few weeks ago I changed the cable for monitor used in recording screen number 1 from display port to display port, to a display port to HDMI.

I switched back to the display port to display port cable. I also backed up configuration info for vMix, uninstalled vMix, RE installed vMix, and restored settings. I am no longer seeing the unwanted artifact in vMix/recordings.

I’m curious to the possibility that this system (hardware & software) may be sensitive to the PC/OS ordering of the monitors. Of my 4 monitors, the PC/OS seems to change which monitor is selected as the “default” screen to show the BIOS boot screen. Etc. if I use my DispayPort to DisplayPort cable, then my screen number 1 for recording is chosen. If I use the DisplayPort to HDMI cable, then a different monitor is selected as the boot up screen.

This shouldn’t make a difference, but it is the only change I’m aware of. Of course this reassignment of monitors means I need to adjust the screen input assignments in vMix as well.

Anyhow, seems to be working now. I’ll provide an update again in a few days after I’ve recorded more depositions.