The BBC is aiming to reduce the lag experienced by streamers watching live sport – fans watching on traditional TV can be far ahead of the action.
- Public trial of low latency streams.
- Available to viewers using a select few devices.
Ahead of the BBC’s live coverage from Wimbledon and Glastonbury, selected iPlayer beta users will have access to a low latency version of the BBC Two live stream. This should significantly cut the delay between the version of BBC Two broadcast via Freeview, satellite and cable and the iPlayer.
The move was confirmed in a BBC blog post, which explained the move will help the broadcaster “assess how well low latency streaming approaches perform over today’s internet into our viewer’s homes.”
The problem with reducing latency is that there’s little time to respond to changes in internet connectivity. The way the internet works means there are many different parts of the chain between the BBC and you. If there are sudden changes, the stream may become more liable to buffering. Chris Poole, Lead R&D engineer at the BBC, confirmed the broadcaster is using technology called Low Latency DASH with chunked CMAF segments.
The delay when streaming is most noticeable during sports events. Streamers might hear their neighbours watching via a traditional TV service cheering a win up to a minute earlier.
Devices that support low latency BBC iPlayer trial
Not all devices support the solution deployed by the BBC to reduce latency. As a result, only users in iPlayer beta using the following devices can benefit:
- 3rd generation Amazon Fire TV Stick
- 2nd generation Amazon Fire TV Stick 4K
- Samsung CU8000 and CU8500 TVs
More devices are expected to be added during the course of the BBC iPlayer trial.
Other requirements
- The low latency BBC Two stream is live between 9am and 5pm.
- You’ll need to have one of the above devices and have enabled ‘iPlayer beta’ in the settings menu.
- You’ll also need to have your iPlayer region set to England and Scotland. That’s because there isn’t a low latency version of BBC Two Wales or BBC Two Northern Ireland.
iPlayer lag was significantly reduced in 2023
RXTV reported in 2023 about an iPlayer upgrade cutting the typical lag to around one minute.
But the delay will always vary between users.
In simple terms, the streaming experience – and associated delay – can vary considerably due to factors such as your connection type, your distance from the router, which wi-fi frequency band you use as well as the device you’re using and how efficient it is at processing data.
There are some factors out of your control, including how data is being routed between you, your internet service provider and your home.
Across my devices at least, the lag between live Freeview broadcasts and the iPlayer is currently at least 43 seconds, but can be as much as 61 seconds. I found variations both between devices and the channel being streamed. The BBC says the typical lag should be “around 40 seconds”. However it acknowledges the delay “is not the same for all viewers”.
By: Marc Thornham