BBC reduces latency for live UHD 4K streaming

• Live 4K user trials showed that latency was a serious issue for viewers
• BBC R&D team has come up with a solution to solve this problem
• Goal is to deliver OTT video with comparable latency to traditional broadcasts
• NFV, edge computing and 5G will all play a role

Over the summer, the BBC conducted a major user trial of live UHD 4K and HDR streaming during the World Cup and Wimbledon. Live transmission OTT is far more challenging than VOD programming, which is why the UK broadcaster decided to conduct this major user trial. Whilst it produced amazing results, one of the main user issues was that of latency and lag. To coincide with the IBC event this year, the BBC announced that it has developed a new technique that it says can solve the latency problem, using techniques that reduce the duration of each streamed segment and also create these segments progressively as a series of chunks that can be passed through the chain immediately they become available.

So where does this sit with the emergence of Edge Computing and 5G, which promise to offer incredibly low data latency and hyper-local caching? It's a critical area to get right, given that the BBC has stated that streaming of all content will be the norm in the near future... and yet more traffic load to be carried over telco networks.

According to the BBC research team, the current difference in latency between broadcast and OTT-delivered services also makes it difficult to combine or switch between the two. Whilst not an obvious concern, this is important for the development of synchronised experiences, dual screen services and content substitution. Therefore its goal is to deliver high quality TV and radio OTT with comparable latency to today’s terrestrial and satellite broadcast services. Reducing the latency requires technical improvements in several areas – there is no single magic bullet. There’s the encoding itself, there’s the distribution path through the CDN (or multiple CDNs), there’s the telecom networks and last mile connections, and there’s the buffering within viewers’ TVs and video-enabled devices. Commercial solutions, therefore, are still several years away.

Filmed at IBC 2018, Amsterdam, The Netherlands