First login to your Moodle Sever via FTP.
Then browse to… in my case using Moodle 1.99,
I went to:
Search for loop, replaced loop=true with loop=false (4 separate instances will need to change).
I can confirm that this does work and can not see any issues by changing this tag to false. It just stops a video file from looping, if you want a mp4 to loop just return and change the loop back to true.
Hope this helps,