Question / Help OBS NDI Frame Rate Progressive Slow Issue

shinhito

New Member
Hello!

I recently was able to make a second dedicated Gaming PC and have been using the OBS NDI Plugin to stream between my gaming PC and streaming PC. Unfortunately, I've recently started experiencing a strange issue where everything is fine on the Gaming PC side (no frame drops, or messages, and the OBS stats window has no red messages) and then everything also seems to be okay on the Streaming PC side as far as OBS messages are concerned (again no glaring issues in the stats window) but the frame rate progressively slows down from 60fps to somewhere like 1 frame per 10 seconds. The audio remains uninterrupted but the frame rate is a slideshow. This issue is immediately fixed by Unchecking and then rechecking the 'Main Output' box under the 'NDI Output Settings' on the Gaming PC. But many times I don't even know it's happening until one of my viewers mentions something and then if I'm in the middle of an Overwatch game, I have to wait until I'm in a spot to quickly hit the 'Main Output' checkbox. The issue also seems to happen randomly, it doesn't happen when I have increased network traffic or when there's increased CPU/GPU usage on the Gaming PC. Many times it happens after about 40-50min of streaming.

Here are some clips of the issue I am experiencing:
https://clips.twitch.tv/FaintGeniusPepperPJSugar
https://clips.twitch.tv/SincereHorribleMarjoramCoolStoryBob

The first shows how everything is running at 60fps but then progressively slows to a slideshow, and the second shows the issue but then how it's immediately fixed by toggling the NDI Output Settings 'Main Output' checkbox.

I have gigabit ethernet on both computers and they are connected via gigabit enabled router. I double-checked to make sure that the speed listed on both the computer's ethernet status windows was 1.0 Gbps. I also tried different ethernet cables to make sure that wasn't the issue and I have had the issue with both PCs running Cat6 and Cat7 ethernet cables. I have also tried changing the 'Sync' method on the NDI Source on the Streaming PC, but each option seems to give the same issue.

The Gaming PC's log from the stream clipped above is here: https://obsproject.com/logs/MRGtD2JeGZ-EBJ2N
This is the Streaming PC's log from the same stream: https://obsproject.com/logs/NPqIOo_9rtZTo1zP

Any help or suggestions for things that I could try is greatly appreciated! This issue has been driving me insane!
 

Narcogen

Active Member
It looks like you may be sending NDI output on both machines, which might cause resource and/or network issues. You should only need NDI output from the machine you're gaming on, to send to the one you're streaming with.

Are you using any Dedicated NDI Filters on scenes or sources? I seem to have noticed that these consume more resources than the main Preview or Program outputs.
 

shinhito

New Member
It looks like you may be sending NDI output on both machines, which might cause resource and/or network issues. You should only need NDI output from the machine you're gaming on, to send to the one you're streaming with.

Nope, only the Gaming PC has the Main Output enabled. The Streaming PC only has one NDI Source.

Are you using any Dedicated NDI Filters on scenes or sources? I seem to have noticed that these consume more resources than the main Preview or Program outputs.

And no, nothing like that. Initially, when this issue came up, I attempted to use them to separate out an Audio source from the video in hopes to fix it. But it still had the same issue so I reverted back to the single NDI Source on the Streaming PC.
 

Nardella

New Member
You can run the following tests.

Try doing a very large network file transfer between the two machines and monitor the rate over time. If the rate decreases after a while then the issue is likely your network.

Try another test using NDI tools Scan Converter (on the gaming pc) and Studio Monitor (on the streaming pc) without OBS running on either. This will help determine if OBS is the problem. If that is the case, you can try using scan converter as your source instead of OBS.
 
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