Using two instances of OBS to record two cameras

[SawyerR]

Hello,

I run a podcast and use OBS to record 4K video into an iMac. The chain looks like this: Sony 6300 > Micro HDMI to HDMI cable > Elgato Cam Link 4K > iMac > OBS
The iMac is Intel based with Radeon Pro Vega 56 graphics.

I'm trying to run two instances of OBS to record a second camera angle using the same setup. The problem is I'm getting the "Encoding Overloaded" error and I'm dropping frames. When doing the in 1080p it works well, but 4K seems to be too much. I've tried adjusting the encoding settings, using hardware and software encoding, and adjusting the bitrate, but nothing seems to avoid the "Encoding Overload".

Is there hardware I can get that will do the encoding for me to take the strain off the computer resources? We are a fairly large podcast so we can afford gear to make this work, I just want to avoid having a get a second computer just to record one more camera.

Thanks for any help!

 

[AaronD]

Is there hardware I can get that will do the encoding for me to take the strain off the computer resources? We are a fairly large podcast so we can afford gear to make this work, I just want to avoid having a get a second computer just to record one more camera.

What if you retire this machine and replace it with a monster? Then you haven't increased the count, right? And it would work like you're thinking of.

 

[SawyerR]

What if you retire this machine and replace it with a monster? Then you haven't increased the count, right? And it would work like you're thinking of.

So you’re thinking I’m just lacking in resources? I wasn’t sure if that was the issue due to the Vega being suited to video work (though I know this is an older GPU). Are there GPU/CPU lines that would be best suited to multi video encoding?

 

[AaronD]

So you’re thinking I’m just lacking in resources? I wasn’t sure if that was the issue due to the Vega being suited to video work (though I know this is an older GPU). Are there GPU/CPU lines that would be best suited to multi video encoding?

Don't know the details of that, but I *can* share what I'm using myself:

Operating System: Ubuntu Studio 22.04
KDE Plasma Version: 5.24.7
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3
Kernel Version: 5.15.0-88-lowlatency (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-4940MX CPU @ 3.10GHz
Memory: 31.3 GiB of RAM
Graphics Processor: Quadro K5100M/PCIe/SSE2

Ubuntu Studio – A free and open operating system for creative people.

ubuntustudio.org

That's on a 2015 Dell Precision M6800 Mobile Workstation. It took a lot of manual effort - trial and error on the command line because I kept killing the graphical environment - to find the exact right driver for this old GPU that would also play nice with the modern OBS. Newer hardware won't have that problem.

I know it's not a Mac, but that's one data point that works. I run two simultaneous instances of OBS, one "Master" to produce the feed to an online meeting as if it were a normal live stream, and the other "Slave" to produce the display for a local audience and record that. The "Master" has a bunch of automation in it that the "Slave" follows, using the Advanced Scene Switcher plugin in both of them, so the operator only has to focus on the "Master". Audio is in a DAW, outside of OBS, and connects to both instances and the automation. And of course, the meeting itself. All on that one machine, no problems.

Advanced Scene Switcher

This plugin will allow you to automate various tasks using "Macros". Macros consist of a list of conditions under which a list of actions will be performed. Examples and guides can be found in the wiki. Feel free to contribute! If you run...

obsproject.com

 

[SawyerR]

Don't know the details of that, but I *can* share what I'm using myself:

First of all, thank you so much for this info and for helping me with this question.

Would you be willing to share your encoding settings? Also curious what resolution you are recording in?

Thank you!

 

[AaronD]

First of all, thank you so much for this info and for helping me with this question.

Would you be willing to share your encoding settings? Also curious what resolution you are recording in?

Thank you!

1920x1080p30

I know that's the streaming settings, but the recorder is set to use the stream encoder, so these are the relevant settings. Since I'm not streaming, I keep thinking I should switch from the streaming-optimized CBR to the recording-optimized CQP, but I haven't yet.

And I remember now, that I had an encoder crash in the middle of one of those meetings, so I switched from NVENC to VAAPI. That might have something to do with my driver issues on this old GPU? Anyway, VAAPI has been reliable on this machine ever since I switched to it, so I'm keeping it. A different rig does use NVENC on newer hardware - same OS - and it works just fine.