Real-Time Messaging Protocol (RTMP) is a proprietary network protocol developed by Macromedia (now owned by Adobe Systems) for real-time streaming of video, audio, and data between a server and a flash player. RTMP was designed for high-performance transfer of video, audio, and data between a server and a flash player, and it has become a popular choice for live streaming on the web.
RTMP operates over a persistent connection, which allows for low-latency communication between the server and the player, and it supports the transfer of multiple streams simultaneously. It is widely supported by many streaming platforms, such as Adobe Flash Media Server, Wowza Streaming Engine, and Amazon Web Services (AWS).
However, with the rise of HTML5 and WebRTC, the use of RTMP is declining as web browsers now support real-time streaming without the need for a flash player. Nevertheless, RTMP remains a popular choice for live streaming in some industries, such as gaming and events, due to its reliability and performance.
Here are some useful links related to RTMP:
Adobe's official RTMP specification: https://www.adobe.com/devnet/rtmp.html
RTMP in the Wikipedia: https://en.wikipedia.org/wiki/Real-Time_Messaging_Protocol
A technical overview of RTMP: https://streamingmedia.com/Articles/Editorial/Featured-Articles/A-Technical-Overview-of-RTMP-81363.aspx
RTMP server software:
These resources should provide a good starting point for understanding RTMP and how it can be used for real-time streaming.