NDI video intermittently distorted

[David Wolf]

I have 3 NDI cameras and I'm using OBS to switch them into Zoom Desktop, and I'm finding that there is intermittent smearing at the bottom of the video and up to 2/3rds of the frame. It seems there is still over head on the CPU and GPU. The PC, Windows 10, has an AMD FX chip with an Nvidia card, I don't have the spec handy, a few years old. See the following image. I have a newer Intel PC with livestream studio and we never see this issue on that PC, so guessing it's somewhat hardware related vs network or camera related. Would be interested to hear if anyone else has seen this. Thanks!

 

[Lawrence_SoCal]

Each NDI stream has to be decoded/decompressed on receiving end. And there are different versions of NDI (both in terms of release, current being v5; and HX vs non HX)
So depending on your setup and specific settings, overwhelming an older system with 3 separate video inputs, then doing real-time video encoding is certainly plausible.

Just as driving a vehicle blind-folded is a bad idea, doing computationally demanding work and not monitoring hardware resource (CPU, GPU, RAM, Disk I/O, etc) utilization is just asking for trouble. Windows has Task Manager [Performance tab] and/or Resource Monitor] you can use to see if (in your case, I suspect more in the lines of a confirmation of) your system is being maxed out with your settings ...

Now with that said, depending on specifics, optimizing the Operating System (to reduce unnecessary load), and OBS, may suffice on the older PC

 

[David Wolf]

Thanks Lawrence, I'm very familiar all you have mentioned.

Is there any type of log or other metric that would help identify the root cause of this distorted video? Maybe a log or something that would have a message that there is not enough cpu/gpu in the system, etc. ?