In the video streaming industry, the Secure Reliable Transport (SRT) protocol is emerging as a revolutionary technology. It promises to transform remote audio-visual production. This article examines the SRT protocol in detail, including its functionality, development history, and the benefits it brings to the industry.
What is the SRT Protocol?
The SRT, or Secure Reliable Transport, is an open-source video transmission protocol. It stands out for its ability to provide high-quality, low-latency, secure video transmission over noisy and unpredictable networks such as the public internet. The SRT protocol offers advanced features that ensure secure and stable transmission of high-definition videos. Indeed, even in standard Internet environments, it guarantees reliable distribution.
The SRT protocol is managed and supported by the SRT Alliance, an organization founded by Haivision and Wowza. The goal of this alliance is to promote the interoperability of video streaming solutions. As a result, collaboration with industry pioneers has been established for low-latency network video transmission.
How Does the SRT Protocol Work?
SRT establishes a dedicated link between the source (encoder) and destination (decoder) for packet control and recovery. Using its own method of packet loss recovery and UDP packets, the SRT protocol adapts to changing network conditions. When the network is poor, additional packet buffers can be added to improve video quality. However, as the network improves, latency can be reduced to offer a near real-time streaming experience.
The SRT protocol can traverse firewalls between the source and destination through three models: rendezvous, caller, and listener. However, the latter model requires participation to configure the traffic transfer, so that traffic received at the public IP address and SRT port of the destination device is forwarded to the device on the local network.
Development History of the SRT Protocol
The SRT protocol was born from the collaboration between Haivision and Wowza. It became open-source in 2017, and since then, it has been supported by over 130 companies collaborating with the SRT Alliance. In fact, over 50 compatible products are currently available on the market, including IP cameras, encoders, decoders, video gateways, OTT platforms, and CDNs. Thousands of organizations worldwide use the SRT protocol in various applications and markets.
Benefits of the SRT Protocol
The SRT protocol offers significant advantages in remote audio-visual production:
Security: The protocol supports AES encryption to ensure end-to-end secure video transmission.
Reliability: With Forward Error Correction (FEC) technology, the protocol ensures stable transmission, compensating for packet loss and bandwidth fluctuations.
Low Latency: Based on the User Datagram Protocol (UDP), the SRT protocol resolves the high delay issues of the UDP and offers low-latency video transmission.
Direct Connection: The protocol allows a direct connection between the signal source and destination, eliminating bottlenecks and reducing network costs.
Transmission Synchronization: The protocol resolves transmission synchronization issues and supports real-time streaming of high-bitrate files and ultra-clear videos.
SRT Protocol Use Case: Low-Cost Sports Event Production
To illustrate the impact of the SRT protocol in the industry, consider ESPN, which deployed SRT-equipped devices in 14 sports conferences. Thus, thanks to the protocol, ESPN was able to produce over 2200 events using low-cost internet connections, eliminating the need for expensive satellite uplink services. This initiative allowed ESPN to save between 8 and 9 million dollars, effectively demonstrating the efficiency and potential of SRT in large-scale content distribution.
PEEBLE and the SRT Protocol
The post-covid era has seen the emergence of SRT protocol broadcast deployments, whether for sports events or corporate events.
We deploy national multisite connections using dedicated FTTO fiber links and fixed IP addresses, covering venues such as halls, stadiums, and sports centers. In parallel, we implement an optical infrastructure at the core of a "remote post-production center," where audiovisual broadcast team resources are centralized.
The goal is to enable direct connections with or without field OB vans for providers like AMPvisual, Eurofilm, etc., leading to the Remote Production Center, on an architecture using this protocol. This allows for highly secure, reliable, and low-latency audiovisual transmission.
We enable partner production teams to rely on low-cost public Internet connections to transmit audiovisual streams in real-time and with stability.
The SRT protocol in the video streaming industry brings new possibilities for live sports and event broadcasts, allowing substantial savings while offering high-quality, real-time audiovisual streams.