Simple MovieTextures and Chrome / Safari 9 issues

Hi there, i'm testing the "Simple MovieTextures for Unity WebGL" asset and i have some issues on chrome and Safari.
I'm using Unity 5.3.4f1.

If i try to play .mp4 video from Edge or Firefox, it works perfectly, but when i try to use it on Chrome (version 52.0.2743.116 m) the video slows down from time to time, like mini freezes.

I get the same issue on Safari, well, it's even worse, the start of the video is very slow, like the first 1/5 of the video (it seems to play like 1/10 of the normal speed) then the rest plays normally.

I thought maybe the texture which displays the video doesn't have the same aspect ratio of the video, but i can't find how to get the video width and height.
I tried using WebGLMovieTextureWidth and WebGLMovieTextureHeight, but it returns 0.

I tried playing the video on the rotating cube, stop the rotation of the cube or playing it on a plane with a scale of 1, but i still get these issues on chrome and safari .

Anybody experienced the same issues and have a solution, or maybe a hint to give me ?

Thanks for reading