Bug Report Consistent ~500ms of frames dropped every ~30s

All-in-one Mighty

New Member
Hello beautiful people and happy new year,

I've been using OBS for 2 years with little problems, switched more than a year ago to OBS Studio, and I recently experienced a very bizarre frame dropping on my live streaming. Basically, everything runs super smoothly with no issues, but every 30 seconds, OBS drops around 500ms of frames.

You can see this in action on this video: https://gaming.youtube.com/watch?t=16385&v=R5E9DGNk04g

Starting shortly after that point on the video, the stream hangs for 500ms, and does the same every 30s in the next 2mn30s, except once. But it continues after that, and I can't figure out what's going on.

A few things:
  • I have a GTX 980 with NVIDIA drivers 388.71.
  • I've been using OBS with no issues for a long time, it just started recently.
  • No major change on my end, no new anti-virus, no new software, no (...) except one thing: I'm now using ASIO4ALL v2 as the output of my sound processing for my microphone, where before I was using the normal Windows WaveOut. Interesting thing here: I had to start doing this a while ago because my microphone would start to crackle heavily on stream otherwise. Not sure where it came from, but I would be surprised if this is my issue. It could be though, I'm gonna try streaming using the previous system.
  • In the background of my streams, except when I'm playing a game, I have a media playing continuously that I never close. Maybe it generates some "lag"? Note that all my media are longer than 30s, so I highly doubt it's that.
  • I think that OBS actually shows the frame skipping when I'm streaming. Said differently, the preview seems to be affected.
  • It only seems to start after a few minutes of streaming, at the start of my stream it doesn't seem to be happening for at least 5 minutes.
  • I've got a bunch of scenes that have missing assets, but I do not use them right now. I don't think it could create this issue.
  • I have 12 Mbps of upload, I only use 9 Mbps for OBS, CBR. I don't think this is a bandwidth problem.
  • I'm using audio at 48khz and 192 bitrate.
  • OBS shows no dropped frames, the game that I play is perfectly smooth and does NOT slow down every 30s, which made this bug difficult to see (since it happens only every 30s).
  • I'm a developer myself, so I'm happy to run tools or try debugging things if you folks have an idea where to look.
Not sure what else I can provide. I'll go ahead and on my next stream and try to not use ASIO4ALL and see if it has an impact.

Thanks!
 

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Boildown

Active Member
01:08:53.349: Output 'adv_stream': Number of lagged frames due to rendering lag/stalls: 13991 (1.3%)

Rendering lag implicates the GPU usually. Make sure you're frame limited on your game and/or have V-Sync ON, or else the GPU can be overloaded by maxing it out drawing very high framerates. OBS needs some GPU time regardless of NVEnc.

Other than that, your scenes seem to have a lot going on and you're using a webcam. I'd make the simplest possible scene, with your webcam and Elgato device unplugged, and see if it still happens. If not, start adding things back one by one until it re-occurs, and then you have your culprit.

It only seems to start after a few minutes of streaming, at the start of my stream it doesn't seem to be happening for at least 5 minutes.

This makes me suspect that something could be overheating. You're getting rendering lag, but I'd measure your GPU and CPU temps.
 

All-in-one Mighty

New Member
This makes me suspect that something could be overheating. You're getting rendering lag, but I'd measure your GPU and CPU temps.

Oh that's a possibility. I would still be... suspicious, as I don't see why it would be so very consistent in terms of timing. It would be surprising that the graphics card overheats exactly every 30s, regardless of what is happening on stream (it also happens when I'm not playing a game). It feels more like a buffer that fills up over time at a constant rate, and is emptied somehow when it become inoperable. Maybe the webcam? In my local tests, disabling every source including the webcam and re-enabling them one by one didn't do much, but I haven't tried to do that for 10 minutes each time (due to how much time it would take).

I'm going to run more tests. Maybe it's coming from the NVIDIA drivers, too? I like to update them often.
 
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