Download and prepare a Raspbian Lite Image

Install the desktop environment:

sudo apt-get install lightdm

Next run the following commands:

sudo aptget update

sudo aptget install y git

git clone https://github.com/adafruit/pi_video_looper.git

cd pi_video_looper

sudo ./install.sh

Next edit /boot/video_looper.ini

Change the configuration to look in the pi folder for the video isntead of the USB drive.  Like so:

#file_reader = usb_drive

file_reader = directory

Be sure to change the default password then you are done as long as you copied a video into /home/pi

Reference: https://learn.adafruit.com/raspberry-pi-video-looper/installation