They’ll announce this feature at GDC 2017.
I’m slammed at my day job right now, but hopefully I can put some images and videos together early in the new year.
I am not de-lighting the incoming footage although that is somewhat possible. Because the footage is currently applied to a flat plane the lighting in game should be considered supplemental to the real world lighting in the source footage. I would say that a high key lighting setup for the green screened subject could provide the right balance between perceived depth (lighting in game is occurring on a flat plane, no way to self shadow) and presence in the environment.
I’ve built in controls to blend between the unlit source footage and the lit result in engine. It’s also possible to color correct the footage before sending it into the engine.
I’m looking forward to the videos. Alas I need it for CES in early Jan so I’m probably going for the simpler option as I’ve already got some thing composited in OBS working. What do you do for camera calibration? Do you read in files in the standard Vive calibration format?
CES is the reason I’m so slammed right now! 
For camera calibration I save the camera variables in a saved game file. I have in game models of the Vive controller being tracked as well as the camera it’s attached to. I do calibration itself in three steps:
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Have someone wear the Vive and try to reach out and touch the virtual camera model’s lens with their controller. As they’re doing this someone at the computer is interactively adjusting the camera position offsets using key inputs. Once the ‘player’ is touching the real camera lens the position can be assumed to be as accurate as necessary and shouldn’t need adjustment in future steps.
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While viewing the composite adjust the rotation offsets of the camera interactively until the physical controllers roughly align with the virtual controllers (it’s useful at this stage to have vive controller models that you can temporarily enable in game to align).
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While viewing the composite adjust the focal length of the virtual camera until the physical controllers are fully aligned at the correct scale. Go back to step 2 and make any further adjusments necessary.
I find that by following the steps in this order it becomes a much easier process. It also helps me to think of the rotation adjustment step as sliding the virtual frame in 2D under the physical footage and the focal length step as scaling the virtual frame. The position of the camera is the only thing that really affects perspective and by having the player reach out and touch the physical camera we’ve set the perspective fairly accurately from step 1.
Of course this is not really possible through editing a text file, it’s only feasible when you can modify values interactively in-game.
I was planning to use something like / to write out a “standard” file and then load that in, so I wouldn’t need to build that adjustment behaviour into my application. Having a nice work flow for calibration would be good but I’d love to allow users to reuse it between applications. Plus I’d like to try saving ones for our different lenses, if the rest of the setup stay static enough.
Upvoted! Absolutely critical to make highquality promo material, and perhaps some other uses as well… Trello
We are also waiting for it. I hope we will get it soon.
The good guys at Epic should please understand that a lot of Youtubers don’t review your game if they can’t do mixed reality videos. PLEASE FIX MIXED REALITY for UE4!
+1 for this!
No mention of it in the 4.15 P1 release notes 
Hi I ve seen a few mixed reality videos using the Xbox Kinect and the vive, I would like to try this but have t a clue where to start, does any know how to do this or has anyone done it and wouldnt mind sharing how it was set up thanks
+1 for this!
I am also waiting for this!
Chiming in, this would be a really useful feature for showing off VR titles.
Was upset not to see it in 4.15 p1. Hopefully, it’s not too long down the road. Any more words on working pull requests?
UE4 VR-Mixed Reality Vive Game Beta - YouTube I was able to get Mixed Reality working in unreal engine, if theres enough demand I’ll make a tutorial. I don’t think it’ll be long from epic, though.
Yes! I dont know why you wouldnt make a tutorial when so many peoples are waiting for this feature.
Awesome. It looks really good especially the depth split layers you show. A tutorial would bring you much kudos I predict!
Please, please, we need THE tutorial, where is the tutorial?
+1 this !
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