Question / Help Frames missed due to rendering lag

[jeremyflint]

I am routinely dropping frames when I stream to YouTube.

Current setup:
PTZ Optics 20X 3G-SDI > Magwell USB Capture > iMac 5K 2017 > OBS Studio > Youtube Live

I have 3 cameras that are all separate inputs into OBS Studio. I am attaching a copy of my latest log file. Can someone take a look at it and offer some tips?

 

[Narcogen]

It looks like you're outputting 720p30, which your machine should be able to handle easily. But you're getting dropped frames both for rendering and network.

Are you putting all 3 cameras through a switch and then SDI into the Magewell? Or are you using three separate capture devices?

 

[jeremyflint]

I have each camera running to its own Magwell device.

 

[Narcogen]

Hmm. If you created a scene collection with the same number of inputs, but from different sources-- say, display or window captures-- does the same thing happen? I guess I'm wondering if the problem is really that the GPU is having trouble rendering all the frames, or if you're having trouble getting full throughput from all the capture devices simultaneously.

It seems to me you should be able to do this without this issue, especially at 720p30.

 

[jeremyflint]

I am also running a display capture scene to grab keynote slides from my local display. I think 1 or 2 of my input cards are actually going into a USB3 hub rather than directly into the back of the imac. Maybe switching them to the onboard USB would help with throughput?

 

[Narcogen]

Possibly? I'm not sure how many discrete USB3 controllers are in the iMac.

 

[jeremyflint]

So apparently Studio Mode is what was causing the dropped frames. Once I turned off studio mode, i went straight to 30fps, less than 1% missed due to rendering lag, etc. Even with the multiview open. I guess I will try running that for a while to see how it works.

 

[Alan McFerrin]

I try to check in here once a week, missed a few weeks. I too have had dropped frames with rendering when in studio mode. I only use studio mode when I add in new images or media and need to size it to match my output. I still drop frames but nowhere as many as in studio mode. I read that it's a known issue and that they are working on it. How do you capture audio? Just curious. Right now I have one device that captures audio and one captures video because neither would do both in OBS correctly. Both worked great in Adobe Live Media Encoder.

 

[jeremyflint]

We are using a Midas M32 digital board. I pull 2 monitor channels from it Via XLR using a Tascam USB 2x2. That gives me a USB in to my iMac that I set as the audio source for OBS.

 

[MaxMattingly]

Just wanna say that, roughly a year after you've posted this, the suggestion to turn off Studio mode on my iMac has resulted in fantastic results, and fixed the headache I was having. Thank you!