Arkit App Losing Touch functionality, mediaserverd crash?

Unity Engine
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1

Hi guys ,

As told in another thread, we are currently running an iOS app with arkit 2.0 in a museum environment on 24 iPad Pros (the new model with depth cam).
The app involves face tracking, where the user can wear different virtual hats, collect items and play mini games. Everything works quite ok, but now that the app is live, running all day and being used by hundreds of visitors, we are seeing some weird issues daily.

From time to time, it seems that the app loses the ability to recognise touch events.This involves gui buttons on a canvas but also onmousedown events on colliders not working anymore. All other stuff in the app still seems to work (arkit video and tracking, rendering, sound, networking,…). We have not yet seen this happen under our own eyes, so we don’t know if there are any reproducible users interactions that trigger this. We just get called on site whenever there seems to be a problem like this. Only way out seems to restart the app, which is not trivial since it runs in guided acces mode.

The reason I’m posting this here is that when we look at the crash logs, the only unusual thing we see is a crash file generated by “mediaserverd” around the time it happened. See the attached file for an example.
There’s not a crash log of our own app (since it didn’t really crash with this issue).

I’ve looked around for info about mediaserverd, seems to be an iOS process or something, but it’s exact use is a bit vague to me. Sometimes it is attributed to processing sound or image files.

When we look at the mediaserverd crashlog however , it says it crashed mostly in thread 15 or 16, which seems to have to do something with a capture session, so I’m guessing the camera(feed).

Does anyone have a clue what might be going on here?
Is there any possibility that mediaserverd crashing might cause our touch input not working anymore?

We are using Unity 2018.3.12f1
Cloud built with xCode 10.1 for iOS SDK 12.0, running on iPad with iOS 12.2

regards,
Jelle

4452163–408259–symbolicated mediaserverd 20-04-2019, 13-12.txt (89.9 KB)

2

Hi everyone,

I’m a colleague of Jelle, currently working on the same project. I have an update on the issue above. The core issue seems to be that the Unity VideoPlayer is sometimes randomly crashing (with the mediaserverd crash log mentioned above).

The touch not working anymore was a side-effect of this, since we deactivated a UI panel when the video had looped. But if the video crashes, it doesn’t loop so this (invisible) panel was never deactivated and still captured touch input, causing this input never to reach the UI buttons underneath. For now, we have worked around this by making sure the panel no longer accepts raycasts. This means that when the video crashes, the panel is still not deactivated, but users can just click through it and don’t even notice that it is there.

Fact remains that the video is crashing when it shouldn’t be. We cannot reliably reproduce this issue, it only happens once every few hundred activations, and we can find no specific trigger condition for this. Does anyone have any similar experiences with VideoPlayers crashing, or pointers on where to start looking for issues?

Regards,

Jeroen

3

We got some additional crashlogs.
Again it is mediaserverd, but the exact thread and reason for termination seems to have some variations.

4486894–413260–mediaserverd CORRUPTED PTHREAD 23-04-2019, 12-53.txt (91.6 KB)
4486894–413263–mediaserverd SIGSEV 24-04-2019, 11-51.txt (106 KB)