I did a test by taking some videos from the 'Movie' folder and, using artificial intelligence, I managed to improve the resolution and apply some filters, but after I put the file back in the folder, the game no longer recognizes it.
I kept the same file extension: .AVI

I wonder that there is a "video player" inside the game that doesn't support better quality videos.

Thanks!!
Gracias, amigo!

I could convert the file, however it looks like it makes it worse again, haha.

Well, it's an early '90s codec meant for full motion video on ancient hardware. Here's an article by someone experimenting with the Sintel trailer and cinepak compression. They use some extra parameters to control quality.

You could also get the video files from the PlayStation disc and convert 'em to get the extra frames from those. Although you might want to skip the intro cutscene because it will be the censored one, you can still source the uncut first zombie encounter video from the Biohazard release.

You don't need the PC low quality footage to restore anything, Some German or French versions of RE1 PSX have the intro fully uncut, both in B&W and color.

[UPDATE]
I found a software called jpsxdec_v2.0, it converts the files from .STR to AVI, however for an unknown reason it doesn't detect audio.

I also perceived that the movies from PSX are kinda similar with the same resolution, so I don't think that would be a big improvement.


I tried that, the issue that I got was the movies in PSX are in .STR format.

I tried to find a converter but they seem to be old softwares that don't work properly on Windows 10.

I also tried to use FFMPEG, but it didn't recoznize the STR movie file.

It's unexpected that Germany, of all places, would get an uncut release on the console. Innit? And wouldn't those versions have baked in subtitles for the intro like the Japanese version has? jPSXdec should allow you to extract those in many ways. First, expand the STR and click on the video stream. Then, take a look into the Save section to the right side. Finally, choose format.

The video files found in PlayStation discs are fifteen (15) fps. PC version ones are ten (10) fps. You can use FFprobe, which comes with FFmpeg, to get data about the streams inside the files.

It's weird but probably a goof on whoever built those games. Also no subtitles baked into the movies, those are added on top in real time.