Question / Help Encoder Overloaded—single source.


New Member
After doing a few 1080p streams to Youtube with web cams and camcorders via Elgato Camlink 4K, i then used a Black magic design ATEM switcher. The single switched stream was somehow taking more cpu load than the previous week broadcast. I saw message about encoder overloading but didn’t know how to fix it. When I got home I was not able to get it to fail as it did when I needed it most. Now my YT VIDEO is almost unwatchable. So, I want to be prepared this week... my switcher was setup for 1080p 59.94 since my crappy camcorder only outputs that signal via HDMI. Btw: my 2012 MacBook Pro has ssd and 16gb ram and running High Sierra. Also, I think the hard drive is encrypted via File Vault, I forgot about that. But, what could cause success with multiple cameras connected versus a single source from the switcher which did not do well? Does OBS run well with Mojave? Are any of you Mac users thinking about buying a PC laptop just for OBS? From what I can tell it seems that OBS is more full featured and more powerful on windows do you agree?


New Member
I'm not a very experienced OBS user, but I will try to assist. I'm assuming that you are using the same camera resolution setting for the Elgato and ATEM. I have been using the original ATEM Television Studio and am looking at software options as a replacement.

Your Mac is using cpu because it is changing the format of the ATEM input from 1080p 59.94 to whatever your OBS resolution is set. How this transformation is done depends on the software and/or hardware controlling the conversion. It's possible that the Elgato offloads this processing to your video card, thus taking the load off of your cpu. Some capture devices have hardware built in to transform the stream so that their is no impact on cpu resources. There is also a resolution setting for the UVC source in OBS. Is it set to use the original source? If so, OBS is not performing any conversion.

The ATEM is sending the raw video directly to OBS. OBS is likely transforming your video source using the CPU instead of the video card or the Elgatos potentially built-in hardware. Is there a resolution setting for the Blackmagic input? Is there a conversion methodology choice?

Your 2012 MacBook Pro's processor is an antique and likely won't perform well. We were asking our 2014 iMac i5 to grab the ATEM input and stream using Livestream Producer and were limited to low resolution streams. The resources used by the ATEM software and Livestream Producer overwhelmed the processor.

One last hint about ATEM. Our problems were exacerbated whenever we transitioned the input in ATEM. During that process, ATEM temporarily doubles the required cpu resources; it's processing the live and preview programs simultaneously. We could watch our processor go from 50% to near 100% whenever we changed the source, often crashing the Mac and forcing us to stream in lower resolution. The Mac was replaced with a Ryzen 3950x PC, which doesn't even know that it working:) You don't need a Ryzen 3950x. I temporarily brought in a budget Ryzen 2200G PC that is similar speced to the iMacs i5, but in real life had no problems handling what the i5 Mac could not. Modern processors are just way more efficient.