High Efficiency Streaming Protocol

High Efficiency Streaming Protocol (HESP)

High Efficiency Streaming Protocol (HESP) is an adaptive bitrate streaming technique that enables high-quality streaming of media content over the Internet delivered from conventional HTTP web servers, just like HLS and DASH. The technology was developed by THEO Technologies and made available via the HESP Alliance, which has Synamedia and THEO Technologies as founding members.

Architecture

HESP leverages two complementary streams: an initialization stream and a continuation stream. The initialization stream is a stream with all keyframes. This stream is only used at startup. At that moment, the most recent image available in the initialization stream is requested. As the initialization stream’s images are all keyframes, playback can start immediately, resulting in very fast channel start and switch times. Subsequently, through a range request, images are requested from the continuation stream, a regularly encoded stream for low latency purposes. HESP is delivered over HTTP/1.1. It uses Chunked Transfer Encoding (CTE) at a very granular level, i.e. each chunk is a frame, to allow for ultra-low latency delivery. HESP requires implementation in the packager and player, and support for range requests and CTE in the CDN.

Standardization

Work on HESP started in 2018; it became an IETF information draft in May 2021.

The HESP Alliance, launched in 2020, promotes and catalyzes the adoption of HESP. It consists of streaming vendors and media companies, including Synamedia, THEO Technologies, G-Core Labs, EZDRM, Mainstreaming, NativeWaves and Hoki. The HESP Alliance technical working group is focused on further advancing the HESP standard.