Question / Help Multiple OBSs and Game Cap - Possible?

[JasonVP]

Hey folks -

I think the answer is, "You're SOL, dude," but here goes: Can someone clarify for me whether multiple copies of OBS Studio running can capture the same full screen game? I'm unable to make it work, and I assume it just means: it can't.

Here's the setup:
OBS Studio is running on my Win10 and using the NVENC encoder to stream a 50Mbit/sec to my local (headless) FreeBSD server. There, NGINX grabs the RTMP stream, fires off FFMPEG to compress the snot out of it to 6.5Mbit/sec, and then broadcast that to Twitch.

All good.

Prior to adding a face cam, I was also using the same OBS process to record. But now that I have said (ugly) face cam, I don't want that in the recordings. Just the stream. So I thought: maybe I can run multiple copies of OBS Studio; that way I don't have to build myself a streaming PC for this.

I set about configuring 2 different profiles with 2 different sets of scenes, etc. The first is for streaming and includes the face cam. The second: recording, and no face cam. I can run them both without a problem: they load up their profiles, etc. Easy peasy. But when I try to capture the full screen game in both: no good. Whichever OBS process is running first gets a hold of the game. The other: just a blank screen.

Is this expected? I don't want to run the games in FS-windowed mode; there's always a performance hit. And again: I'd like to avoid building a streaming PC. Also, running a second, alternative piece of recording software is doable, but I'd rather avoid that. I like OBS. :-)

Am I SOL?

 

[JasonVP]

Since posting this, I've gone some more experimentation. Ultimately I think it's a case of multiple OBS processes not being able to hook into the game simultaneously. And if that's the expected result/limitation, then we're all good. It means I'm SOL. :-)

Anyway, experiment 1: Based on some feedback on Reddit, I re-did the Recording profile to use "Desktop Capture". This worked, but the resulting recording was very choppy at 59.94FPS. I couldn't really tell if it was a keyframe, B-frame, or some other issue. But the results were unwatchable/unusable.

Experiment 2: I tried using Playclaw's NVENC recorder just for game recording. That also worked full screen, but the resulting recording was identical to the first: very choppy.

I'm guessing they're both due to the same issue: multiple processes trying to grab onto the hardware encoder. But, I'm not positive. That's supposed to be allowed with the encoders, but perhaps not.

Anyway, I'm open to other suggestions. The goal is to stream and record with as little (eg: close to 0) load on the gaming rig. Hardware isn't a concern; my GPUs are 2 Titan X Pascals in SLI and an overclocked 7900X processor. Neither of which have been taxed in the least during this set of experiments. I'd like to keep it that way so I have lots of headroom for the things that matter: games! :-)