RTMP
Also called Real-Time Messaging Protocol.
Adobe-originated streaming protocol that survives as the ingest format nearly every streaming platform still accepts. Largely replaced downstream by HLS and DASH, but the encoder-to-platform hop is still overwhelmingly RTMP.
Stewarded by Adobe (specification published), maintained in practice by platform vendors.
Continuous streams that are large enough to be sized properly, and that must arrive in order and on time.
What kills it. Anything that starves the link — usually a management transfer nobody scheduled — and jitter that outruns the receive buffer.
Ports
What it carries
- Resolution
- Not fixed by the specification
- Frame rate
- Not fixed by the specification
- Video compression
- H.264 video with AAC audio, frozen there in practice
Video: RTMP fixes no resolution or frame rate; the encoder decides both and the platform sets what it will accept. What is effectively fixed is the codec pair, so newer codecs need extensions that not every platform takes.
What goes wrong
What speaks RTMP (2)
| Product | Direction | Notes |
|---|---|---|
| OBS Studio OBS Project |
out | RTMP output is the default path to almost every streaming platform. |
| vMix StudioCoast |
out | Streaming. |
Typical use
- Pushing a stream from OBS or a hardware encoder to a platform
- Ingest into a CDN for onward HLS delivery
- Simple venue-to-cloud streaming
Sources
- RTMP specification — Veriskope primary
Known gaps on this entry: implementations. If you can source one of them, that is a ten minute pull request.
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