OBS Takes Over AJA Kona Card, Even When Not Used As a Source


New Member
Hey there! I have an unusual setup in which I use two capture cards. One I use for capturing to OBS, then I take that card's passthrough and feed it to my AJA card for recording ProRes video through the AJA Control Room software. A recent OBS update though has broken this workflow.

When I open AJA Control Room, I am able to see my video going into the AJA card.

When I open Elgato's 4K Capture utility, I can see video in both pieces of software.

When I close 4K capture utility and open OBS, I can see video in OBS, but the AJA Control Room preview disappears and says "Device in use in other app".

My AJA Kona card is not currently set up as a source in OBS, verified by going to add an "AJA I/O Device" and the list of existing devices is empty

From the Tools drop-down menu I've checked AJA I/O Device Output settings. Both populate with a device "0 - Kona LHI (number). Below that, output is set to "select...", format is blank, pixel format is YUV-8, and Auto-Start on launch is disabled.

I suspect that OBS is grabbing the card on startup despite not being used by OBS, and takes control away from the Control Room. Does anyone have any ideas for how I can prevent this from happening?

I know that as a possible workaround I could try futzing around with doing source recording, and going down the ffmpeg parameter rabbit hole, but I would really prefer OBS just not block me from using my card in other apps unless I actually choose to use it in OBS...

OBS Log file attached.

Any advice would be extremely appreciated!


New Member
Update: Updated OBS to the current version (27.2.3,) updated log file. AJA Control Room no longer gives the error message, but the video preview still freezes when OBS opens and Control Room is still unable to record new files while OBS is open.


  • 2022-03-11 10-11-40.txt
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New Member
Figured out a fix for this myself by deleting the files in the OBS Plugins folder starting with "aja" and restarted. Both work fine now.