PIR to trigger video clip on big LCD display

I have been asked by my son to make a device to trigger a video clip from a usb stick, whenever somebody walks near the screen.

I have searched the forum, and it seems most questions have been about feeding video through the arduino - which of course it cannot handle.

The Rasberry Pi comes to mind , or the new 17 Devices And New Technologies as Small as Computer Chip or Business Card , but I have no idea of how to write code for them, and no time to learn !

I asked him what device he has in mind to play the video, and he reckons the usb stick can be plugged into the monitor ( I am so out of touch with these things, we are still watching a 26" CRT tv at home ! )

If he can get a monitor with a usb stick storage mode, it seems at first glance that it would be best for me to emulate the remote control with the arduino and send them infrared ?

Any advice from you guys who have played with multimedia ?

That makes sense: my colleague has an LED projector which plays video direct from a flash drive, and it has a remote, so that's entirely do-able.

On Dave Whatsisname's EEV blog, he has a few video clips about reverse engineering a remote's codes. Iirc, he fires the remote at Arduino, analyses on scope, then programs Arduino to transmit those very codes as if it was the remote. You'll need to search his blog.

If the display is just a standalone monitor then using an PRi would be a good approach.
(USB plugged into RPi & RPi plugged into display vis HDMI)

If the display is a PC or MAC etc, then adding a Leonardo with PIR acting as a keyboard(HID) for the PC would work well.

what code did you use?