RTMP
Stands for "Real-Time Messaging Protocol." RTMP is a protocol designed for transmitting audio and video over the Internet. It is used to stream multimedia content on demand and also supports live streaming.
Streaming over RTMP requires a media server, such as Adobe Media Server (AMS). Clients connect to the streaming server over TCP, typically using port 1935. RTMP stream URLs typically use a format such as:
rtmp://stream.domain.com/livestream
History
Macromedia created RTMP. Adobe acquired Macromedia in 2005, including the rights to RTMP, which was part of the Flash technology platform. While RTMP can stream Flash formats (such as .SWF, .FLV, and .F4V), it supports many other types of audio/video transmissions as well.
Since the use of Flash has decreased, RTMP has become more commonly used to stream standard compressed video audio and video rather than Flash media. Adobe has also made RTMP an open specification, which can be used by third-party applications. Examples include Nimble Streamer, Open Broadcaster Software, and Wowza Streaming Engine.
NOTE: As of 2020, sales and support for Adobe Media Server, Flash Media Live Encoder, and the RTMP SDK are provided by Veriskope rather than Adobe.