Softvelum Low Delay Protocol (SLDP)

StriveCast Streaming Dictionary

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What is the Softvelum Low Delay Protocol?

The Softvelum Low Delay Protocol (SLDP) is an Internet protocol developed to support Ultra-Low Latency video transmissions after support for Flash was discontinued.

Why was SLDP developed?

In 2017, Adobe announced that they would discontinue support for the Flash protocol they developed in 2020. Flash was used in combination with RTMP worldwide to transmit video and was ideal for transmitting video in Ultra Low Latency. The Flash protocol was responsible for implementing interactive browser applications while RTMP transmitted the video and audio. After Abobe stopped the support for Flash at the end of 2020, Flash and RTMP remained because there was no suitable alternative for Ultra Low Latency Streaming. HLS, Mega-Dash, and other protocols had also taken their share of the market, but they were less well suited to support Ultra Low Latency streaming.

When do you need Ultra-Low Latency?

In some use cases, it is critical that virtually no time elapses between the moment of action and viewing on the end device. Such use cases might include:

  • Live sporting events
  • Gaming
  • Betting
  • Safety reasons

Softvelum, therefore, developed SLDP to provide an adequate replacement for Flash. In doing so, the developers made streaming with Ultra-Low Latency possible and included all the modern features that were not yet given in the days of RTMP. The following features therefore characterize SLDP:

Approximately 2 seconds delay: Between the original and the player are on average about 2 seconds so that one can speak of Ultra-Low Latency.

Codec Agnostic – You can play or deliver any codec that the end user’s platform requires.

ABR support – Modern features like ABR are fully supported.

Synchronized playback – SLDP supports synchronized playback, which becomes relevant when multiple devices are playing the same stream simultaneously, and audio tracks must be prevented from overlapping.

Firewall-friendly – SLDP works on the basis of HTTP / HTTPS and can thus be described as “firewall-friendly.”

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