BBC R&D claims solution to ‘World Cup iPlayer lag’

The BBC’s research and development arm claims to have solved latency issues when streaming content live over the web, compared to watching it on broadcast TV.

After complaints that iPlayer viewers experienced delays of up to 30 seconds while watching World Cup football matches online this summer, the BBC says it has come up with a way to eliminate the lag between web streams and broadcast feeds.

At IBC in Amsterdam this week BBC R&D will showcase low latency techniques that can solve the issue – though the BBC cautions this is just a prototype and is “unlikely to change live streaming delays any time soon”.

“Obviously, viewers were frustrated this summer hearing goals go in before they saw them, or finding out about a red card decisions on social media first,” said Chris Poole, lead research engineer for BBC R&D.

“That’s why we’re so excited by the results of our experiments, and we’re hoping that the demonstration we’ll be showing at IBC will help accelerate the work taking place across the industry to eliminate long delays from internet streams.”

Latency issues occur because of the way video is distributed over the internet, explains BBC R&D. Portions of video and audio data are typically delivered in separate files, known as media segments, that must be generated and processed before they can be passed on to the next step in the chain.

The techniques BBC R&D has been experimenting with include either reducing the duration of each segment or creating the segments progressively in sections that that can be passed through the chain immediately as they become available.

“What we’re showing at IBC is a prototype,” said Poole. “To roll it out properly will take time, and it needs coordination with the whole industry, so viewers shouldn’t expect the lag to disappear imminently. But perhaps by the time they’re watching the next World Cup, viewers will be cheering at the same time, regardless of how they’re watching the match.”

At IBC this year BBC R&D will also demonstrate its latest work in personalising TV broadcasts by mixing internet-delivered and broadcast video, and present a study comparing video compression performance of different coding standards.

Earlier this year, the BBC’s chief technology and product officer, Matthew Postgate, predicted that “the days when all media will be distributed over the internet are not too far away,” and said that the question is “not when, but how we [the BBC] will make the transition to being an internet broadcaster”.

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