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Tips for DK2 ext mode preview, hdmi/judder/double vision

vaughamhong
Level 2
Hey,

I just got a new Win 8.1 laptop (Asus ROG G751JT) and spent an afternoon getting everything to work. I thought I'd share everything I learned in hopes it can help people save some time. There is also a little trick at the end that helps those who demo a lot and want a cheap / easy solution to preview what the user is seeing without messing around with Direct mode / Extended mode landscape/portrait mirroring madness.

1. HDMI - HDMI cable provided by DK2 may produce image with green dots
When using the HDMI cables provided by the DK2 on our Asus ROG G751JT, we see a distribution of bright green dots. The fix that works reliably is to use a normal HDMI cable - which unfortunately means another wire to manage. I ended up using the HDMI cables from DK1. This may just be a case of having a bad DK2 HDMI cable. I wonder if this has anything to do with the HDMI hardware based encoder/decoder - to keep the wires thin.
Also, for our Asus ROG G751JT, the HDMI needed to be pushed in a little harder for proper contact.

2. Direct Mode Judder
When running our our own in-house native OpenGL based application, we found that at certain points a judder like effect would all of a sudden happen without warning. It is as if the timewarp timings are off and you see a consistent ghost of the last frame as you move your head. This does not happen in extended mode @60/@75hz, but only in direct mode. When this happens, turning the DK2 off/on (using the button on the HMD) cures this until it happens again. Not a very good solution when you're giving live demos, but it points to an SDK/Runtime bug. I'm curious as to if this works for other applications - must do more testing. I'm planning to dig into this and report back, unless Oculus fixes it sooner in their next SDK.

3. Double Vision
See viewtopic.php?f=20&t=19418
Even with the new 347.25 drivers, I still see double vision in a specific case. This seems to happen in extended mode mirroring - and only when the primary display is in Portrait (DK2 in Landscape). With the Asus ROG G751JT, if the display is in Landscape (DK2 in Portrait) the NVidia drivers do not split the screen and produce double vision. This is something that is out of the community's hands and will require NVidia to get this fixed.

4. Direct mode-less, extended mode mirror-less previewing of the user view
For those of you who want a simple way to preview what a user is looking at without running in direct mode or messing with portait / landscape modes when using extended mirroring, there is a super easy way that is low cost and time (Win7/Win8). Set up your DK2 to be in extended mode without mirroring - so that the application only shows up in the DK2. With the taskbar on your primary display, you can mouse over an application to display a real-time preview. Unfortunately it's pretty small - but we can make it bigger! All it takes is adding / tweaking the Windows registry.

a. Open RegEdit
b. Navigate to HKEY_CURRENT_USER/Software/Microsoft/CurrentVersion/Explorer/Taskband
c. Add a new DWORD key value named "MinThumbSizePx"
d. Enter 500 (max in pixels)
e. Restart and mouse over should now display a larger preview of the extended mode application running in DK2
http://www.csarchive.net/2012/12/change-win-7-8-taskbar-thumbnail-preview.html

Hope this helps. πŸ˜„ πŸ˜„ πŸ˜„

Vom
6 REPLIES 6

pittsburghjoe
Level 4
1. wrong, are you high? You have to use the supplied hdmi cable to use the positional tracker sync cable.

2. sounds like a parked core issue

3. ..wrong ..latest driver 347.25 has a working version. If you had .09 installed ..you have to uninstall it before installing .25 ..otherwise the bad code remains

4. That actually sounds pretty cool 8-)

vaughamhong
Level 2
1. To clarify, the green dots seems to only happen with the supplied DK2 HDMI cable on our Asus ROG G751JT. Using any other standard HDMI cable produces a clean image. Maybe we just got a bad DK2 HDMI cable. Also, the HDMI cable has nothing to do with the positional tracking.

2. Thanks for pointing me to the 'Parked Core' issue. I'll take a look at this sometime tonight. Much appreciated.

3. Hmm, that's weird. I did an uninstall / install several times with the same results. It still amazes me that driver related shenanigans still exist.

pittsburghjoe
Level 4
The camera directly connects via a sync cable to the hdmi cable. no?? Does it magically work without it?

vaughamhong
Level 2
The tracker USB / Sync cable connects to the DK2. The DK2 has a USB / HDMI combo cable that connects to the PC. I'm talking about the HDMI cable from the DK2 to the PC. The one we have is problematic (green dots) when plugged into our Asus. We replaced it, and now it's fine. We have not touched the tracker's USB / Sync cable configuration.

pittsburghjoe
Level 4
ohh, okay, sorry

vaughamhong
Level 2
So many cables πŸ™‚ Can't wait to port our work to the GearVR. But Android NDK is another form of torture.