solved Broken DMD capture in VR

[kiloNova]

Hello, wonderful people! I suddenly broke my ability to capture an external DMD while playing in VR. The odd thing is, I had been playing Ghostbusters (using PastorLUL's amazing new masterpiece, of course!) in VR for hours last night before going to bed. I haven't made any changes to my system since, yet DMD capture suddenly broke out of nowhere. To narrow down the problem, I confirmed that my DMD colorizations are all working properly in VPX 10.8.0.2058 64 bit. I also confirmed that VPX GL 10.8.0.2058 64 bit works normally when playing in VR with 'Capture external DMD' disabled. However, when loading a table in VPX GL 10.8.0.2058 64 bit in VR with 'Capture external DMD' enabled, I have received several similar errors when running different tables. When running The Sopranos table, I receive the following error: "Capture: Failed to create duplication output." When running the Terminator 2 table, I get this: "Capture failed with error message: The keyed mutex was abandoned." When running the Ghostbusters table through VPX GL 10.8.0.2051 32 bit, I receive this error: "Capture failed with error message: The application made a call that is invalid. Either the parameters of the call or the state of some object was incorrect. Enable the D3D debug layer in order to see details via debug messages."' In T2, I could see the first frame of the color DMD output, but The Sopranos and Ghostbusters displayed nothing, just the plain backglass (I don't capture the backglass, to clarify)

 

From what I was able to find by searching, this appears to be a problem with D3D api calls. I'll provide some background info but feel free to ask for anything else that could help. VPX is fully updated as of 2-3 days ago and it had been working perfectly with no issues until today. In case it could be related, I was working on setting up P-ROC two days ago so I could finally try out Cactus Canyon Continued. I used the SkeletonGame installer (https://skeletongame.com/files/proc_env_installer_wHD.exe) and replaced my 64 bit version of Python 2.7 with the 32 bit version. In this process, three new path variables were added:

C:\MinGW\bin
C:\P-ROC\cmake\bin
C:\P-ROC\DLLs

Like I mentioned, everything worked fine afterward so I doubt it was related but I thought I should at least mention it in case python could be part of the issue. If you have any suggestions or even wild ideas, I'm very much up for trying anything.

[kiloNova]

Solved! I continued working on the issue for hours. I restored a backup of VPinMAME from two months ago to rule out any recent updates causing the issue. It changed nothing so I shifted my focus away from VPX and on to Steam VR. I thought the current beta (2.12.1) had been installed days ago so it was way down the list of my suspicions but I figured I would rollback to the latest stable release as a hail mary. Suddenly, everything worked again! If anyone else experiences this issue, rollback to the latest stable release of Steam VR and you should be good to go.

 

I hope this helps someone else and saves them from banging their head against a wall for 8 hours  Finally, feel free to reach out if you happen to experience the same issue—I'm happy to help since I've learned a great deal while untangling this mess.

Edited June 11, 2025 by kiloNova

[papasergio73]

hi can you tell me how to downgrade steamvr and where to download the previous version Thank you