OBS 31: frames freeze with multiple capture devices

[angeloruggieridj]

OBS Studio Log URL​

https://obsproject.com/logs/swQiLe8F1M23NyAr

Expected Behavior​

Stable flow using more than one capture device card (in this case Elgato CamLink 4K).

Current Behavior​

Using two Elgato CamLink 4K devices for multiple camera sometimes the video stream in Preview or On-Air it's not fluid (visibile on 0:16 of the following video).

As the example video, there are some seconds where I notice it on Preview and On-Air panels but also the stream and the recording is also affected.

The configuration for both of source is:

• Preset: High [I could try only to change it to 1920x1080, no option available about FPS personalization as I've write here: https://obsproject.com/forum/thread...e-the-frame-rate-of-elgato-camlink-4k.183286/
• Buffering: disabled

Other info:

• input stream coming from both cameras are 1080p at 50fps
• Canva dimension is 1920x1080p, 50fps
• downscale dimension is setted to 1280x720p
• Recording use the same encoder as the live stream.

Both of CamLink are connected to a USB 3.2 hub 10Gbps ports.
I've tried also using two independent and different USB hub, same problem occours.
Using also two independent USB-C ports and not a hub (considering that Mac has only two USB-C ports) have also this problem.

Using the same configuration (single hub with the two Camlink connected) and selecting one of the Camlink for Skype (for example) doesn't verify the problem, so the video has not lag or freeze.

Steps to Reproduce​

1. Connect two video capture devices
2. Switch between them

 

[jet7]

On MacBook M1/2?

OS version?

Having the same issue!

And this issue has plaqued OBS at least 6+ months!

OBS dropping frames and getting these "surges" repeately

This issue has persist over 8 months now. It happens even when OBS is not streaming or recording at all. The preview windows shows clearly that it drops frames. Then suddenly it is normal again without any missed frames. And this happens over and over again.... Have re-installed OS and...

obsproject.com

( OBS Forum: "Awaiting approval before being displayed publicly.")

 

[jet7]

Since it takes ages for this new thread to get approved, I will post it here also..

OBS dropping frames and getting these "surges" repeately​

This issue has persist over 8 months now.

It happens even when OBS is not streaming or recording at all.

The preview windows shows clearly that it drops frames. Then suddenly it is normal again without any missed frames. And this happens over and over again....

Have re-installed OS and everything to te latest versions.

Even changed the power supply to a beefier one.

Setup:
MacBook Air M2, 8 GB RAM.
Latest MacOS
Latest OBS

Full HD video at 25 fps is coming in from BMD UltraStudio Recorder 3G SDI with Thunderbolt 3 cable.
Few NDI sources are also brought in from ProPresenter

Before this issue started to manifest we had no issues at all even when we used Full HD at 50 fps!

This issue is also present on our MacBook Air M1, 8 GB RAM that has similar inputs.

 

[jet7]

To me this seems some kind of weird Sync -issue OBS is having and it happens at least with recent OBS and MacOS.

And the bad behaviour seems to escalate when "changing/swiping screens / apps" on MacOS and then the result is very choppy streams as many on the forum has already mentioned.

 

[jet7]

Here is a good example:

- YouTube

Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.

youtu.be

OBS is used here to bring all layers together and stream to YouTube and record the final output on Mac.

Flawless mixed SDI signal is coming from vMix to OBS 31.0

 

[jet7]

I'm on an iMac and fairly new to OBS, but technically savvy too. I have several apps open including OBS. Whenever I switch between apps using the keyboard shortcut CMD + Tab, OBS generates an error message.

Switching Apps Keeps Generating Error Message From OBS

I'm on an iMac and fairly new to OBS, but technically savvy too. I have several apps open including OBS. Whenever I switch between apps using the keyboard shortcut CMD + Tab, OBS generates an error message. It's not the end of the world, but it's more of a nuisance. Is there any way to stop...

obsproject.com

Interesting. Could that be the cause one of issues talked above?

 

[angeloruggieridj]

On MacBook M1/2?

OS version?

Having the same issue!

And this issue has plaqued OBS at least 6+ months!

OBS dropping frames and getting these "surges" repeately

This issue has persist over 8 months now. It happens even when OBS is not streaming or recording at all. The preview windows shows clearly that it drops frames. Then suddenly it is normal again without any missed frames. And this happens over and over again.... Have re-installed OS and...

obsproject.com

( OBS Forum: "Awaiting approval before being displayed publicly.")

MacBook Pro M1 / 16 GB of RAM

OS: macOS Sequoia 15.2

 

[AaronD]

Using two Elgato CamLink 4K devices for multiple camera...
...
...Both of CamLink are connected to a USB 3.2 hub 10Gbps ports.
I've tried also using two independent and different USB hub, same problem occours.
Using also two independent USB-C ports and not a hub (considering that Mac has only two USB-C ports) have also this problem.

I think the problem is USB itself, not the captures, and not OBS.

The data rate that is required for a good HD video capture, is over half of what even "fast" USB can support. So one is okay, but when you add a second, it can't keep up.

If you have multiple USB controllers, then you can have one good capture per controller, but if you only have one controller and an internal hub (cheaper to build that way), then you're limited to just one.

---

How portable is your rig? Or how portable does it have to be? If you can have a desktop tower instead of a laptop, then you can use a multi-input PCIe capture card instead of USB. Then all of its inputs are good simultaneously, and it's often cheaper per input than good USB too.