Video Best settings for videoplayer

HI!
I'm using the Unity videoplayer for 3 or 4 full screen videos in 3 or 4 displays.
The problem is that the videos aren't very smooth. The pc can support 4 video, in fact the performance of the CPU and GPU are under 30% and the unity build is fixed at 61 fps (I fixed vsync at 60).

Is there some setting to optimize video perfomance? Or should I use some other video player?

P.S. the video is not perfectly smooth even if I use only 1 video. In the editor seems a lot better than the build....

P.P.S I'm using unity 2017 (I tried 2018 or 2019 but the problem is the same and I need to use 2017) on windows 10

 

HD videos (720p) works great.
Encoder Profile : Baseline
Encoder lewvel : 3
Encoder Preset: VeryFast / Fast / Medium
FPS: 30fps

Works on Android /IOS.
Used HandBreake (it's free) to make conversions. Always in mp4 (h264)

 

Thank you! I'll try