Real-Time Messaging Protocol or RTMP was developed originally by Macromedia, which then became Adobe. It was a system to implement streaming of video, text and audio over the internet between a flash player and a server with the RTMP setup.
Using fragments between the server and the user, it maintains a stable connection and because of that it has low latency, meaning that there is a very short delay, between the server and the user. The delay is perhaps 1 or 2 seconds.
The RTMP servers available are Adobe Media Server, Red5, Wowza Streaming Engine, Nginx RTMP server and a few more, but this 4 are the most common, although Adobe is very expensive and Red5 is difficult, personally I prefer Wowza RTMP, which has a number of advantages, we will talk about this on another post.
Going back to RTMP, it is a TCP-based protocol which maintains persistent stable connections and allows low-latency communication. To deliver streams smoothly and transmit as much information as possible, it splits streams into fragments, and their size is negotiated dynamically between the client and server.
RTMP servers are ideal for live streaming but also for Ondemand video streaming, it is also a necessary component for live video chats.
RTMP Server, how it works
The server must be setup with a media server, like Adobe or Red5, then the video stream connects to the RTMP installed on the server, the video stream could be a laptop with a software installed, this software is an encoder, there are a number of them, OBS Studio, but the most common is the Adobe, FMLE, which you can download free at http://hosting-marketers.com/flashmedialiveencoder_3.2_wwe_signed.msi (for windows computers, Mac computers you can download directly at Adobe site.)
On the encoder you enter the server RTMP, which would be something like this:
Then you connect and start the broadcast. this stream will go directly the RTMP server and you can now setup a player for your users, if you using a RTMP player you will need to use a flash player, but using Wowza Streaming Engine on the RTMP server it converts the stream to a HLS protocol which can be used on many other platforms as well, like smartphones and HTML5 Players. Although the HLS has the latency issue because of the flash players end of live it is nearly impossible not to use it. Nowadays, with a good configuration you can reduce the latency to 3 or 4 seconds.
So we have, YOU on your laptop with a camera and an encoder >>> your internet connection and the RTMP Server connection >>> and finally the player on your site broadcasting your live event. Or your video files.