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Mixed reality capture

December 6, 2016 - 6:24am #1

I am not able to use the Mixed Reality Capture feature in the Windows Device Portal when running my Unity 5.5 app that uses Vuforia 6.1.17. The video player displays an error

"Error:Unsupported video type or invalid file path"

Is anyone else able to use the Mixed Reality Capture feature while running the Vuforia library? Is there any other way of streaming the output of a Hololens application using Vuforia?

 

Thanks

Mixed reality capture

November 16, 2018 - 2:24pm #6

Hello,

The instructions below are for HoloLens device running RS1:

Based upon experiments with HoloLens while running Vuforia, here is what we know about the Mixed Reality Capture (MRC) feature:

  1. You can record videos of Vuforia apps running on HoloLens. Note that for this to work, the app running Vuforia must be started *before* you started to record with HL’s MRC. If you start recording first, the video will abruptly stop once Vuforia gets access to the HL camera.
  2. You *cannot* do MRC Live preview while a Vuforia app is running in any case. If you try to start Live preview while a Vuforia-based app is running on HL, you will get an error in MRC. If you try to start a Vuforia-based app while Live preview is running, the app will not start.

The limitations above are related to real-time camera access for apps running on the HoloLens. In order to guarantee optimal detection and tracking performance, Vuforia is granted sole access to the live camera feed. This is similar to other platforms that we support, such as Android and iOS. You can see that it also works the other way around for apps that do not run Vuforia. The Live preview app requires real-time camera access, so while it is running Vuforia is blocked from accessing the camera.

The instructions below are for HoloLens device running RS4:

Based upon experiments with HoloLens while running Vuforia, here is what we know about the Mixed Reality Capture (MRC) feature:

  1. You can record videos of Vuforia apps running on HoloLens. Note that for this to work, the Vuforia performance mode must be set to MODE_OPTIMIZE_SPEED, which sets the camera capture resolution to be 720p, e.g. 1280x720.
  2. The app running Vuforia must be started *before* you started to record with HL’s MRC. If you start recording first, the video will abruptly stop once Vuforia gets access to the HL camera.
  3. The MRC capture resolution must be set to the same as the Vuforia performance mode (720p)
  4. You *cannot* do MRC Live preview while a Vuforia app is running in any case. If you try to start Live preview while a Vuforia-based app is running on HL, you will get an error in MRC. If you try to start a Vuforia-based app while Live preview is running, the app will not start.

We've had mixed success with these steps in RS4, with results in that it works every time to it works once in a while.

Hope this helps.

Thanks,

Vuforia Engine Support

Mixed reality capture

November 16, 2018 - 6:44am #5

Hi community,

I've hit the same problem.

Has this bug been detected elsewhere / solved?

Mixed reality capture

December 20, 2016 - 6:04am #4

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Mixed reality capture

December 8, 2016 - 6:23am #3

Downloading the logs I see the error returned is "the thread tried to read from or write to a virtual address which it does not have appropriate access". Exception code 0xC0000005

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Mixed reality capture

December 8, 2016 - 2:08am #2

I am also interested in this question, have not been able to stream, but I have been able to record videos. 

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