SOLVED

I want to stream the camera feed from a Tello drone to HoloLens

Occasional Contributor

Hello,

I am using the following tools: 

  • TelloforUnity
  • MRTK v1.0.2104.3 Beta
  • Unity 2019.4.28f1

I want to be able to see the drone's camera feed on hololens. Using only TelloforUnity I am able to see the camera feed on Unity when I start the Scene, but when I try to launch the project to Hololens all I am able to see is a white screen in the area where the video should have played. 

For anyone who is familiar with TelloforUnity, I created a new project, added the MRTK and I added the TelloVideo to my scene. The video works fine in Unity but not on Hololens.

 

Any Ideas how to fix this issue or how to stream a video to Hololens?

6 Replies
For UWP, one good thing to always check it to make sure you've got the correct Capabilities listed:
https://docs.unity3d.com/Manual/class-PlayerSettingsWSA.html#Capabilities

I'm a little rusty here as well, but it kinda looks like TelloForUnity may not even support UWP? I see plugin binaries there for Win32, Android, and Mac, but not UWP. You can see the list of native binaries they have over in this folder:
https://github.com/comoc/TelloForUnity/tree/master/TelloUnityDemo/Assets/Plugins
x86_64 is for Win32, UWP typically has a WSA or Metro folder according to the Unity native plugin docs.

I've got a Tello myself and was pretty excited to try it out with a HoloLens! But unfortunately it's a little tricky to find something that plays nicely with UWP, I haven't found one that met my needs quite yet (I haven't looked incredibly hard yet, just tried out one or two). Fortunately there are a lot of Tello libraries out there, you might have some additional luck looking for stuff that's not Unity specific, like out on NuGet. Or you could always file an issue on the TelloForUnity repository! Maybe someone's still there watching it.

Hello @koujaku, when I open TelloVideoDecoder in Unity, which is located inside the plugins folder in TelloforUnity, I get the option to choose UWP for SDK. I'm new to holoLens programming, but from this I understand that there is a capability for this to work in UWP.

 

I think I found the problem but I don't know how to fix it yet. I managed to view the Unity debug log when I deploy the project to hololens, and I get an exception that the "TelloVideoDecoder.dll could not be found. A dll file is missing" 

 

What do you think?

 

Chrisstyll_0-1625726811327.png

 

best response confirmed by Chrisstyll (Occasional Contributor)
Solution
Oh yeah, that sounds a little more promising!

Given the timestamp on that repository (3 years ago) this is a pre-HoloLens 2 project! HoloLens 1 was an x86 device, while the HoloLens 2 is an ARM64 device. The binary files that were included likely don't cover the ARM64 architecture, which is why you get the missing DLL issue!

This means you may need to compile the TelloVideoDecoder native plugin project yourself for ARM64/UWP to get the proper binaries. In most cases, this should be just switching over those settings and building again.
Thank you, I think this will work!
How did you connect the Hololens2 to Tello?
In my case, I am able to connect to Tello's WiFi but the device is not visible in its network, and hence no communication happens.
I'm using the HoloLens 1 and to connect to tello I just connect HoloLens to Tello's wifi. The connection is handled inside my Unity project.