RTMP
RTMP (Real-Time Messaging Protocol) is a protocol for sending live video and audio from an encoder to a streaming server over a steady TCP connection. Originally built by Macromedia for Flash, it is now used mainly for ingest (the first mile from the broadcaster to the platform). The platform then converts the stream into HLS or DASH for viewers, since modern browsers no longer play RTMP directly.
Why it matters
RTMP is still the simplest way to get a live stream from an encoder into a platform, since almost every encoder supports it. Plain RTMP sends the stream and its stream key unencrypted, so anyone on the network path can read or hijack them. That is a security risk for paid or confidential events. Teams going live on FastPix avoid that risk from the first stream, because ingest runs over RTMPS or SRT rather than plain RTMP, and encoders such as OBS and vMix support both.
How it works
- The broadcaster enters a server URL and a stream key into an encoder such as OBS Studio.
- The encoder opens a steady TCP connection to the server, by default on port 1935.
- Compressed video and audio are sent continuously over that connection as small messages.
- The platform receives the stream, transcodes it and repackages it as HLS or DASH for viewers.
Is RTMP still used?
Yes, RTMP is still widely used, but almost only for ingest, sending live video from an encoder to a platform. Browsers stopped playing it when Flash was retired, so viewers now watch through HLS or DASH. Many platforms prefer RTMPS (encrypted RTMP) or SRT for ingest, since plain RTMP sends the stream key without encryption.
RTMP vs SRT: which is better for live streaming?
SRT is usually the stronger choice over unreliable networks, while RTMP is the simplest and most widely supported. RTMP runs over TCP, which can stall when packets are lost. SRT runs over UDP, resends lost packets within a set time window and includes encryption. For a studio with stable internet RTMPS is fine; for remote or mobile feeds SRT copes better.
What is the difference between RTMP and RTMPS?
RTMPS is RTMP wrapped in TLS encryption, the same protection HTTPS websites use. The video and the stream key travel encrypted, so nobody between encoder and server can read or tamper with them. RTMPS usually runs on port 443, which firewalls rarely block. Most encoders support both, and switching is usually just a change of URL.
Where it's used
Creator apps, live sports producers and event teams use RTMP to send a stream from almost any encoder to the cloud with just a server URL and stream key.
Where it usually goes wrong, and how FastPix handles it
Plain RTMP sends the stream key and video unencrypted, so a leaked key lets someone hijack a broadcast. RTMP over TCP can also stall on lossy networks.
FastPix ingests the secure form, RTMPS, rather than plain RTMP, and also accepts SRT. Existing OBS Studio and vMix setups only need the ingest URL and stream key to send into FastPix over either protocol. Your stream keys stay encrypted on shared networks, and remote crews have SRT for unstable connections.
By the numbers
- RTMP uses TCP port 1935 by default, and Adobe published version 1.0 of the RTMP specification on December 21, 2012. (Real-Time Messaging Protocol, Wikipedia)
