Startup movie cut in half and blackscreen

[VFansss]

Good day to everyone!

I'm making a custom video splashscreen to show at startup but maybe I didn't understand well how to do it. I explain: from rainbow screen at very startup to ES carousel my P2 (without ANY game, I admit. I know that loading lot of games will slow down it a lot) take about 30-35 seconds.

Default sequence is: rainbow screen -> 4 raspberry raspbian startup -> RP splashscreen -> ES spashscreen -> ES Carousel (Ready to play!)

So what's my idea? Make a video more lenght that 40 seconds, so I can skip all various SC and simply:

disable rainbow screen
disable 4 raspberry startup screen

RP splashscreen (my video) -> End of the video -> ready to play

I'm made a video long 45 seconds (1280*720, 30fps, mp4 with h264, like wiki said).
I've loaded it and it work good, except the fact that after about 15-16 seconds of video the screen goes black, my monitor doesn't detect any video source and only after a lot of seconds (I think time that employs the video do end) I find myself on ES carousel.

On the wiki it say that a good startup movie would be long about 10 seconds. Why? I don't understand that... I can't use a more long spashscreen? What is causing this problem? Any advice?

Thanks to anyone for help!