Black screen while video playback in coi app

[matthesatox]

Describe the bug
Playing a received video in coi app shows only a black screen. Audio is hearable.

To Reproduce
Occurrence: [always / 5 out of 10 times / rarely]
Steps to reproduce the behavior:

1. Go to 'chat'
2. Send a video
3. Play the received video in COI App

Expected behavior
Video should be playable

Screenshots
If applicable, add screenshots to help explain your problem.

App information (please complete the following information):

• App version: 0.700.3
• Plugin version: [e.g. 0.4.0]
• Delta Chat Core version: [e.g. 0.40.0]
• Flutter version: [e.g. 1.0]

Smartphone (please complete the following information):

• Device: iPhone 11 Pro Max
• OS: iOS 13.6 (Public Beta)

Additional context
log_20-06-15_08-37-02.txt

Internal Bug Tracker.

[robert-virkus]

Can you attach a video that cannot be played back? Is this happening for an affected video every time or only sporadically?

[Boehrsi]

This happens only sometimes and not for every video right?

[matthesatox]

This happens for some videos always and other videos never. I don't know where the difference is between the videos