If you want to run the script on boot, you should use start.sh. start.sh runs the usb-update script, and then starts playing video.mp4 on a loop. It uses omxplayer (make sure whatever version you use has the --loop option). I would suggest simply adding the following to /etc/init.d/rc.local:
```
+cd /home/pi/hdmi-switcher
/home/pi/hdmi-switcher/start.sh
```