High Efficiency Streaming Protocol
{{Short description|Video streaming protocol}}
{{Technical|date=November 2023}}
High Efficiency Streaming Protocol (HESP)
High Efficiency Streaming Protocol (also known as HESP) is an HTTP-based adaptive bitrate streaming protocol that enables high-quality streaming of media content over the Internet delivered from conventional HTTP web servers,{{Cite web |title=What is the High Efficiency Streaming Protocol (HESP) and why does the video industry need it? |url=https://www.theoplayer.com/blog/what-is-the-high-efficiency-streaming-protocol-hesp-and-why-does-the-video-industry-need-it |access-date=2023-07-04 |website=THEO Technologies|language=en-US}} such as 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.{{Cite web |title=THEO Technologies and Synamedia form HESP Alliance |url=https://www.digitaltvnews.net/?p=34815 |access-date=2023-07-04 |website=Digital TV News |language=en-us}} HESP brings sub-second latency and a fast channel change and is seen as a challenger of Low Latency HLS (LL-HLS, first released in 2009) and Low Latency DASH (LL-DASH, standardized in 2012).{{Cite web |title=Rethink report debunks low latency hype |url=https://www.csimagazine.com/csi/Rethink-report-debunks-low-latency-hype.php |access-date=2023-07-04 |website=CSI Magazine |date=25 May 2022 |language=en-us}}
Architecture
HTTP-based streaming protocols such as HLS and DASH typically use a segment-based approach. This means a video is cut up into TCP segments of a few seconds each, which requires video players to wait until the start of a new segment to start playback. This approach increases channel change times and introduces additional latency. HESP leverages a frame-based streaming approach, which does not require a trade-off between live latency and channel switching time.{{Cite web |title=HESP: Sub-second Latency, Fast Channel Change and Improved ABR over Standard CDNs |url=https://www.streamingmedia.com/Articles/ReadArticle.aspx?ArticleID=153579 |access-date=2023-07-04 |website=Streaming Media | date=22 June 2022 |language=en-us}}
When all components of the video workflow are optimized for low latency, HESP can provide for sub-second latency.{{Cite web |title=HESP: What a HESP protocol is and how it changes streaming for the better |url=https://gcore.com/learning/what-a-hesp-protocol-is-and-how-it-changes-streaming-for-the-better/ |access-date=2023-07-04 |website=Gcore |language=en-us}}
HESP requires implementation in the packager and player, and support for range requests and Chunked transfer encoding (CTE) in the CDN.{{Cite web |title=HESP - Informational Draft |url=https://datatracker.ietf.org/doc/draft-theo-hesp/ |access-date=2023-07-04 |website=IETF |language=en-us}}
Standardization
Work on HESP started in 2018; it became an IETF information draft in May 2021{{Cite web |title=High Efficiency Streaming Protocol (HESP) |url=https://theiabm.org/bamproducts/high-efficiency-streaming-protocol-hesp/ |access-date=2023-07-04 |website=IABM |language=en-US}}
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, EZDRM, Mainstreaming, NativeWaves, and Hoki. The HESP Alliance technical working group is focused on further advancing the HESP standard.{{Cite web |title=HESP Alliance Members |url=https://www.hespalliance.org/members |access-date=2023-07-04 |website=HESP Alliance |language=en-US}}