RTMP is a Streaming Protocol associated with Adobe's Flash Player -- Made Very Popular by YOUTUBE
RTMP is a protocol used by the Adobe Flash Player to deliver real time video, and audio using an IP connection or a polling HTTP tunnel.
The protocol is a container for data packets which may be in Action Message Format or a Format called raw audio/video data found in the Flash Video Format.
Amazingly a single connection is capable of multiplexing many streams using different channels. Within these channels packets are split up into fixed size "chunks".
RTMPT is an HTTP wrapper around the RTMP protocol that is sent using POST requests from the client to the server. Because of the non-persistent nature of HTTP connections, RTMPT requires the clients to poll for updates periodically in order to get notified about events that are generated by the server or other clients.
RTMP is a very robust protocol for Video and Audio and is often the methodology used by CDN's to Ingest Video and Audio into their networks.