(12 April 2022) - THIS POST IS OUTDATED - SQUARESPACE HAS REMOVED THE EMBED '<>' FEATURE ON VIDEO BLOCKS. TO USE THIS METHOD YOU NOW HOW TO ADD YOUR IFRAME IN A EMBED BLOCK. HOWEVER YOU ALSO NEED SOME EXTRA CSS TO MAKE THE IFRAME FILL THE EMBED BLOCK. SEE ANSWER IN POST BELOW.
The best way to do this is to use a squarespace block, Vimeo or Youtube.
I have used the below code inside Squarespace's video block. But instead of adding the link, you can click <> and insert this code below but change out your video ID.
This makes the videos autoplay and loop. You can adjust the controls and sound (background), etc too. See below and screenshot attached for reference.
For an example: I am using it on my SquareKicker website here: https://squarekicker.com/features
Just swap out the Vimeo / YouTube ID number for yours.
VIMEO
<iframe src="https://player.vimeo.com/video/625215456?autoplay=1&loop=1&autopause=0&background=1&muted=1&color=ffffff&controls=0&portrait=0" width="800" height= "500" frameborder="0" allow="autoplay; fullscreen" allowfullscreen></iframe>
YOUTUBE
<iframe width="100% !important" src="https://www.youtube.com/embed/oyuCciYX2S4?playlist=oyuCciYX2S4&autoplay=1&mute=1&controls=0&loop=1" frameborder="0" allow="accelerometer; " allowfullscreen></iframe>
Note: Youtube needs a playlist to loop the video, just use the same video ID
