Transcription of error, for search-ability:

.\ysmovie.cpp(268)
CVideoStream::OpenFile

failed : CVideoStream::OpenFile(8)
Skusit znova (Try again)     Zrušiť (Cancel)

Just FYI (whoever reads this bugreport):

Workaround to get cinematics working: "protontricks 223810 quartz amstream" (found in a ProtonDB entry)

Compatibility Report

• Name of the game with compatibility issues: Ys I
• Steam AppID of the game: https://steamdb.info/app/223810/

System Information

• GPU: GTX 760
• Driver/LLVM version: NVIDIA 440.44
• Kernel version: 5.4.11
• https://github.com/shoober420/linux-scripts/blob/main/home/shoober420/sysinfonvidia
• Proton version: 4.11-11

LOG:
steam-223810movies.log

Game launches, but will display an error message when starting a new game like @Zero86Sk mentioned, because of the game videos. Works perfectly when checkmarking "Disable Movie Playback" with the "Configuration Tool".

Symptoms

Game will display an error message after starting a new game because of movie playback.

Reproduction

Start a new game

https://github.com/ValveSoftware/Proton/issues/3428

Using proton 5.0-9, the videos won't play even if you use protontricks 223810 cinepak directshow, only the audio will play and no error window will popup, but the game will stop/crash there with the music of the cutscene playing. Tried other proton versions, same luck(or just the error popping up).

Steam and system info

https://gist.github.com/krauser87/79c011b7a53a4de7dc07620140571f21

Game log

steam-223810.log

Using proton 5.0-9, the videos won't play even if you use protontricks 223810 cinepak directshow, only the audio will play and no error window will popup, but the game will stop/crash there with the music of the cutscene playing. Tried other proton versions, same luck(or just the error popping up).

Steam and system info

https://gist.github.com/krauser87/79c011b7a53a4de7dc07620140571f21

Game log

steam-223810.log

All the missing libraries from that log are absent from Proton WINE 5.0.9 included GStreamer:

  
(wine:777): GStreamer-WARNING **: 18:35:46.628: Failed to load plugin '/home/krauser/.steam/debian-installation/steamapps/common/Proton 5.0/dist/lib64/gstreamer-1.0/libgstvorbis.so': /home/krauser/.steam/debian-installation/steamapps/common/Proton 5.0/dist/lib64/gstreamer-1.0/libgstvorbis.so: wrong ELF class: ELFCLASS64  
...

You can use system libraries instead by setting winegstreamer disabled:
protontricks 223810 winecfg
Libraries tab -> winegstreamer, Add, Edit - disabled

Also you need to have those libraries in your system. For Ubuntu they are in these 32bit packages:
sudo apt install libgstreamer-plugins-base1.0-0:i386 libgstreamer-plugins-good1.0-0:i386 libgstreamer1.0-0:i386
In Debian it should be something similar.

By the way you don't need cinepak and full directshow for this game's video to work. You only need: protontricks 223810 amstream quartz

@defter-linux Thank you a lot, it's working now

The solution still works in 2025 for Ubuntu 20.04.

At first disabling of the winegstreamer made it seemingly worse (error instead of testing grid).
But after downloading 1.4Gb worth of windows files (needed for amstream quartz) and registering the libs, FMVs are there.