# Ingest protocols

The Dolby OptiView Live platform supports low latency live streaming through two ingest protocols: **RTMP** and **SRT**.

RTMP supports both **pull** and **push** mode out of the box. SRT works out of the box in **pull mode** only, where the platform connects to your encoder to pull the stream. If you need SRT push mode, contact your account representative to have it enabled.

## RTMP — Real-Time Messaging Protocol

RTMP is a widely adopted protocol originally developed by Adobe for transmitting audio, video, and data over the internet. It remains one of the most commonly supported protocols across hardware and software encoders.

* **Pros**

  * **Broad encoder support** — Nearly all hardware and software encoders support RTMP out of the box.
  * **Simple setup** — Requires minimal configuration, typically just a server URL and stream key.
  * **Low latency** — Provides low latency contribution suitable for most live streaming use cases.

* **Cons**

  * **Container limitation** — RTMP uses the FLV container, which only supports H.264 video and AAC audio. Newer codecs such as H.265/HEVC are not supported.
  * **Single audio track** — RTMP is limited to a single audio track per stream, making it unsuitable for multi-audio use cases.

## SRT — Secure Reliable Transport

SRT is an open-source protocol designed for low latency, secure, and reliable video transport across unpredictable networks. It is increasingly adopted as a modern alternative to RTMP.

* **Pros**

  * **Resilient on unreliable networks** — SRT uses UDP with built-in error correction (ARQ), making it well suited for contribution over the public internet or unstable connections.
  * **Multi-audio support** — SRT uses the MPEG-TS container, which supports multiple audio tracks within a single stream.
  * **Closed captions and metadata** — The MPEG-TS container also supports embedded closed captions (CEA-608/708) and SEI metadata pass-through.
  * **Codec flexibility** — MPEG-TS supports a broader range of codecs compared to FLV.

* **Cons**

  * **Less universal encoder support** — While adoption is growing, not all encoders support SRT, especially older hardware models.
  * **More complex configuration** — SRT may require tuning parameters such as latency, overhead bandwidth, and encryption settings for optimal performance.

### SRT passphrase

In **pull mode**, you can secure the connection by including the passphrase directly in the SRT URL that you configure on your channel (e.g. `srt://encoder-host:port?passphrase=my-secret`).

In **push mode**, the Dolby team configures the passphrase for you and provides an SRT URL with the passphrase included.