Steins;Gate 0 [BLJM61303]

I wasn't able to get past the black screen after the stabbing scene until I re-encoded the video like MrComputerRevo did. If I recall correctly the video that plays then is imv008.usm.

I can't manage to pack the video and audio files back to .usm with the ScaleForm VideoEncoder :/
Is there any other program to do it?

You could try making sure you have the original files, and that nothing is modified.
You could try resetting the config (then redoing the settings) and deleting the whole RPCS3 folder(s) to completely reset the folder structure.
Could try also making sure you have the admin rights.

The files aren't modified, I did already extract the .usm files to a separate folder and the videos/audios work opening with a video player after recompiling, so I know they're there.
I've already resetted the config once, but I'll try that again.
I have the rpcs3.exe set to always "Execute as admin" in the file properties.