Viewers watching live television over the Internet today are typically seeing the action with a delay of 30 seconds or more. In future, it won鈥檛 have to be that way. We鈥檙e working on reducing the 鈥榣atency鈥� of internet streaming to match that of broadcast by streamlining the encoding and distribution chain and using new techniques enabled by the MPEG DASH and CMAF standards.

Project from 2018 - present

What we're doing

We鈥檙e putting together a low-latency end-to-end system for prototyping new approaches to low latency and to test their performance.

We鈥檙e also working to understand the network conditions that viewers experience and to model how low-latency streaming will perform under those conditions.

By working with others in the industry through standards groups, we aim to agree common approaches for low-latency streaming that will offer interoperability between content providers like the 大象传媒 and client devices such as televisions and Internet radios.

• 大象传媒 R&D - Reducing Latency - Video Streaming Without the Delay
• 大象传媒 R&D - Dynamic Adaptive Streaming over IP Multicast

Why it matters

We want to give our viewers and listeners the best quality TV and radio experience that we can. Quality is not just about how things look and sound; it鈥檚 also about the timeliness or 鈥榣atency鈥� of the stream 鈥� how soon after an event happens that our audience hears or sees it.

This matters a lot if you鈥檙e watching a football match over the Internet close to a neighbour watching the same match via broadcast. It can be very frustrating to hear someone else鈥檚 reaction to a goal a long time before you see it yourself.

It also matters if you鈥檙e watching a live event and following others鈥� reactions on social media. You don鈥檛 want to read comments about things you鈥檝e yet to see.

The current difference in latency between broadcast and Internet-delivered services also makes it hard to combine or switch between the two. This is something we鈥檇 like to be able to do for synchronised experiences, dual screen services and for content substitution.

Our goals

Our aim is to be able to deliver high quality television and radio services over the Internet with comparable latency to today鈥檚 broadcast services.

We鈥檒l be targeting people with high-performance Internet connections initially but hope that it will be technically possible to deliver reliable low latency services to the majority of our viewers and listeners within a few years.

How it works

Reducing the latency requires attention to all the steps in encoding and distributing the stream. These include:

• getting the pictures and sound to the video and audio encoders
• the time taken for the encoding
• moving the encoded media through our content distribution network
• delivering the media over the Internet to the viewer鈥檚 media player
• buffering in the media player to account for fluctuations in throughput
• buffering and delay in the player鈥檚 video and audio decoders and display

Because much of the Internet is built around moving files around (for example, as you browse the web), Internet video distribution today usually delivers portions of video and audio data in separate files.  and  both work this way. If these files 鈥� known as media segments 鈥� get too short, efficiency reduces and distribution costs rise. If the files are long, you get high latency as traditionally each segment needs to be generated in full before it can be passed on to the next step in the chain.

The low latency techniques we are working on work by either reducing the duration of each segment, or by creating the segments progressively as a series of chunks that can be passed through the chain immediately they become available.

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• 大象传媒 R&D - Reducing Latency - Video Streaming Without the Delay
• 大象传媒 News - 大象传媒 solves World Cup streaming delay
• 大象传媒 R&D - Dynamic Adaptive Streaming over IP Multicast