Emergency 2 won't play video files (977840)

Compatibility Report

• Emergency 2
• AppID: 977840

System Information

• GPU: AMD RX 570
• Driver/LLVM version: Mesa 18.3.1/LLVM 7.0.0
• Kernel version: 4.19.12
• Gist
• Proton version: 3.7-8

I confirm:

• that I haven't found an existing compatibility report for this game.
• that I have checked whether there are updates for my system available.

steam-977840.log

Symptoms

Game launches but video files aren't played back. The video files are supposed to be played before accidents/incidents happen and give the player an idea on how the accident/incident happened

Reproduction

Start game, start a new game, get your first incident assigned (happens automatically), save the game exit the game and start it again, open the loading menu, select your saved game, click 'Video abspielen' -> Window goes black for a split second, then back to normal but no video is played.

Further information

The videos are stored in a subfolder called 'Videos' and are .avi files, codec is MPEG-4 simple profile that can be played back with VLC or totem without issue. The game is in german, I'm not sure if there is an english version. I can translate buttons if neccessary, but using Google translate or something similar is sufficient to reproduce this issue (IMO).

Start with the attached steam-977840.log and reproduce the reported sequence: load a saved game and select “Video abspielen.” Investigate Proton’s video playback handling for the game's MPEG-4 AVI files. Done means the incident video plays instead of briefly showing a black window.