Dark Souls III (374320) crash on starting new game

Compatibility Report

• Name of the game with compatibility issues: Dark Souls III
• Steam AppID of the game: 374320

System Information

• GPU: GTX 1080 Ti
• Driver/LLVM version: nvidia 418.56
• Kernel version: 5.0.6-200
• Link to full system information report as Gist: https://gist.github.com/hhyyrylainen/b37480d424240a4c72a0d1a2a3fbd1a2
• Proton version: 3.16-4 (recommended), same issue also with 4.2-2

I confirm:

• that I haven't found an existing compatibility report for this game. I found a workaround from the following issue but @kisak-valve asked me to open a new issue
  • https://github.com/ValveSoftware/Proton/issues/478
• that I have checked whether there are updates for my system available.

https://gist.github.com/hhyyrylainen/8801236fe770a3ea38f6da72959e5a01

Symptoms

Game crashes when starting a new game. After clicking "new game" from the main menu the game shows a black screen for a second and then crashes.

Workaround

@UndeadKernel found a workaround: https://github.com/ValveSoftware/Proton/issues/478#issuecomment-420053552
Basically just rename the video files to prevent the game from trying to play them. With that change I can start a new game just fine.

The report names no source file or test. Start by reproducing the crash when selecting New Game with Proton 3.16-4 or 4.2-2, then compare behavior with the linked video-file-renaming workaround; done means starting a new game without renaming those files.