RTMP (Real-Time Messaging Protocol)
RTMP is a legacy application-layer audio/video/data messaging protocol over reliable stream transport, usually TCP, still used primarily for live program ingest to streaming servers and cloud platforms. For IT schedules, treat it as an encoder-to-ingest service, not as browser playback, camera pull, local AV distribution, multicast media, discovery, clocking, or a complete security design. Prefer RTMPS where the destination supports it.
Scope: RTMP (Real-Time Messaging Protocol) — select the deployed product/version; optional services require separate selection.
protocol · Catalog reviewed 2026-10-22
RTMP, IETF, SMPTE, IEEE, VSF
Infrastructure Requirements
- A source encoder or software mixer that can publish RTMP or preferably RTMPS
- an ingest server/platform that accepts the exact URL, application path, stream key, TLS behavior, codec set, bitrate, keyframe/IDR cadence, audio format, and optional Enhanced RTMP features being used
- outbound internet or private network reachability from encoder to ingest edge
- DNS
- time/certificate trust where RTMPS is used
- and enough uplink headroom for sustained contribution bitrate plus overhead. Viewer delivery is normally a separate platform output such as HLS / DASH, not RTMP itself.
Network & Physical Requirements
| Port / allocation | Transport | Connection / signal flow | Feature and requirement | Evidence |
|---|---|---|---|---|
| 1935 (default) | TCP | Publisher → Ingest server | Profile requirement · Core RTMP ingest RTMP/TCP ingest; Adobe Primetime Live Packager documented configurable listener example The publisher connects to the ingest server listener. Use the actual ingestion URL/port; TCP 1935 is the documented default for this profile, not an immutable port. | Source checked 2026-10-22 server.xml configuration table: Config/Port default 1935; TCP Socket receive bufferAdobe Primetime Live Packager 1.2 documentation |
| 443 (default) | TCP | Publisher → RTMPS ingest server | Optional · RTMPS RTMPS ingest where supported YouTube RTMPS endpoint; other services may differ Use provider-issued ingest URL, stream credentials and supported codec settings. | Source checked 2026-09-27 Setting up your encoder; connection requirements for RTMPS |
Gotchas & IT Notes
- ⚠IANA-only UDP 1935 or historical port 3500 is not part of this normal ingest profile. HTTP tunnelling is a separate mode.