There is no communication between the player and the encoder. With AES 128 key and CENC Clear key, the player has to retrieve the key either from the manifest, or you need to provide it through the player config. Clear Key and AES-128 are industry-standard encryption formats that are supported not only by our systems, but essentially by most actors within the streaming world. You can therefore use our player to decrypt these formats even if they have not been encoded by our encoder, and you can also encode this kind of content and play it with any system that supports them.
If your assets are ready to play and hosted on the cloud, you can already use our player out of the box with them. If your assets are plain MP4/MOV files for instance, you could use our API to encode them into DASH/HLS.