I'm using a Media Services Live origin

You can apply ultra low latency (ULL) to streamline delivery of your Media Services Live (MSL) 4.x content through AMD.

To apply ULL streaming, you need to meet some MSL 4.x-specific prerequisites and set up an MSL 4.x configuration to support it. You also need to apply some settings in a couple of behaviors in your AMD property. ULL setup for an MSL origin is fully covered in the MSL 4.x - User Guide.