Not sure if this feature is in version 4.2 but might be.
Create a new IPTV mux and for the url you enter a command such as this that points to your video file...
pipe:///usr/bin/ffmpeg -loglevel fatal -re -i /media/ron/external/Movies/garfield.mp4 -vcodec copy -acodec copy -metadata service_provider=FIFO -metadata service_name=Garfield -f mpegts -tune zerolatency pipe:1
Let the MUX scan and a service will be created that can be mapped to a channel.
Obviously ffmpeg needs to be installed on your system.