Real Time streaming to Dolby Millicast

Take a live broadcast below 500 ms of glass-to-glass latency: C21 Live Encoder runs the broadcast on its Real Time encoding pipeline and contributes it over RTMP — or Enhanced RTMP for multitrack scenarios — to Dolby Millicast, whose WebRTC CDN fans it out to viewers with sub-second delivery. The combination fits real-time interactivity: live events, sports, online betting and auctions.

Three pieces make up the flow, all configured from C21 Live Control:

Before you start

• A Dolby Millicast account with a publish token: the Millicast dashboard supplies the RTMP publish URL and the stream name / token pair the Destination needs.
• A low-latency friendly input — SDI, NDI or SRT Channels keep the contribution side of the latency budget tight.
• An Encoding with H.264 + AAC — the safe baseline for Millicast WebRTC playback across browsers and devices.
• Network headroom from the encoder host to the Millicast ingest: sustained upload at the Encoding's bitrate, low jitter.

Via UI

Enhanced RTMP — multitrack contribution

Where classic RTMP carries one video and one audio program, Enhanced RTMP extends the protocol to publish multitrack outputs — multiple audio tracks and modern codecs — in a single session. Cires21 validated the implementation against Dolby Millicast, so the pairing is operational, not just spec-compatible.

Operational differences from classic RTMP:

• Adaptive. Enhanced RTMP is one of the adaptive Destination types: when the Live stream carries multiple renditions, all of them are published (classic RTMP emits only the highest quality).
• Multi-audio. The Live stream's mapped audio tracks travel in the same session — no parallel Destination per language.
• Engage at start. An Enhanced RTMP Destination added to a Destination group while the broadcast is on air engages on the next start, not at runtime (the runtime toggle returns 409 — see Destination groups).
• RTMP Buffer. The RTMP Buffer hint is honoured on the classic RTMP type only.

Via API

Create the Destination with POST /c21apiv2/crud/publishings — Publishing.type takes "RTMP" or "Enhanced RTMP" (the legacy alias ERTMP is accepted on write and normalized to Enhanced RTMP on read):

curl -X POST "https://<your-host>/c21apiv2/crud/publishings" \
  -H "Authorization: Bearer <YOUR_API_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Millicast-RealTime",
    "type": "Enhanced RTMP",
    "settings_common": {
      "provider": "Millicast",
      "urls": { "primary": "rtmp://<millicast-ingest>/v2/pub" },
      "stream": "<streamName>?token=<publishToken>"
    }
  }'

For a classic RTMP Destination, settings_extra.rtmp_millicast_buffer_millisec carries the buffer hint (honoured only when provider = Millicast). The Real time encoding flag is part of the Live stream's configuration — set it from the Live stream editor; then start the Live stream as usual (startLivestream).

Latency budget

Sub-500 ms end-to-end assumes every hop is tuned:

FAQ

Cross-links

• Destinations — the RTMP and Enhanced RTMP types and the provider catalogue.
• Live stream options — where the Real time encoding flag surfaces.
• On air — runtime health of the push.