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Version: v2

Streaming protocols

The media engine outputs your live stream in multiple protocols to ensure broad device and player compatibility. The following output protocols are supported: HESP and HLS. Additionally, WebRTC can be configured at the distribution level for sub-second real-time delivery.

HESP — High Efficiency Streaming Protocol​

HESP is a next-generation streaming protocol designed for ultra-low latency live delivery. It is the default and recommended output protocol for the Dolby OptiView Live platform.

  • Ultra-low latency — delivers end-to-end latency in the 1 to 5 seconds range, significantly lower than traditional HLS.
  • Fast channel switching — viewers experience near-instant startup and channel changes.

HLS (CMAF) — HTTP Live Streaming​

HLS is the industry-standard protocol developed by Apple for delivering live and on-demand content over HTTP. The media engine outputs HLS using modern CMAF (fragmented MP4) segments.

  • Broad compatibility — supported by virtually all modern browsers, devices and players.
  • Higher latency — HLS typically delivers latency of 8 seconds or more, compared to 1–5 seconds with HESP.

HLS (MPEG-TS)​

HLS with MPEG-TS segments is an older variant of HLS that uses traditional transport stream segments instead of CMAF.

warning

Only use HLS MPEG-TS if you are targeting a platform that genuinely does not support CMAF-based HLS — for example, certain legacy set-top boxes or embedded devices. In all other cases, use the standard CMAF HLS output, which offers better performance and broader modern device support.

HLS MPEG-TS does not support all platform features. For example, DVR, Nielsen, and DRM are not available with this output format.

WebRTC​

WebRTC enables sub-second, real-time delivery by connecting a distribution to an OptiView Real-time streaming source. Unlike HESP and HLS — which are configured on the engine — WebRTC is configured per distribution. This allows you to add real-time delivery to specific distributions while keeping standard protocol delivery on others.

  • Sub-second latency — delivers end-to-end latency under 500 ms, the lowest of all supported protocols.
  • Hybrid delivery — works alongside HESP and HLS. The player automatically selects the best available protocol based on priority.

See the WebRTC distribution guide for configuration details and API examples.

API example​

You can configure output protocols via the API using the outputs object when creating or updating an engine.

POST https://api.theo.live/v2/channels/{channelId}/engines

{
  "name": "my-engine",
  "region": "europe-west",
  "quality": {
    "abrLadderId": "your-abr-ladder-id"
  },
  "outputs": {
    "hesp": true,
    "hls": true,
    "hlsTs": false
  }
}