webm videos fail to play inside app

The media player is shown, at least the controls, it just does nothing
reported by @blizzz

I can't reproduce it with Samsung and Xiaomi device.

diagnosis data from Arthur (c.n.c.):

Meta information

Generation of system report

19 Mar 2025 11:38:09
Phone

Device

Xiaomi 23030RAC7Y

Android version

34

Google Play services

Google Play services are available
App

App name

Nextcloud Talk

App version

v21.0.0

Build flavor

gplay

Battery settings

Battery optimization is ignored, all fine

Notification permissions

Notifications are granted

Calls notification channel enabled?

Yes

Messages notification channel enabled?

Yes

Firebase push token

c3MKK...

Latest firebase push token generation

Unknown

Latest firebase push token fetch

13 Mar 2025 19:19:08

Registered users

2
Current account

Server

...

User

...

User status enabled?

Yes

Server notification app installed?

Yes

Latest push registration at server

18 Mar 2025 21:00:51

Latest push registration at push proxy

18 Mar 2025 21:00:51

Server version

31.0.2 RC1

Server Talk version

21.0.1

Signaling Mode

External

Start by reproducing the failure using the reported Xiaomi 23030RAC7Y running Android 34, with the app and server versions listed in the diagnosis data. Trace the Android app's media playback entry point to determine why the WebM video shows controls but does not play; done means the reported video plays successfully.