This pilot offers Radio 3 in the highest possible audio quality so that our audience experiences our output exactly as it left the studio.
Can you sum up the project?
For the duration of the pilot we are providing a simulcast of Radio 3’s live output compressed using FLAC, so it sounds every bit (no pun intended!) as good as when it left us.
How does it work?
We’re using FLAC and MPEG-DASH to deliver losslessly-compressed audio to your browser. This allows us to reduce the bit-rate required for transmission without any loss of information.
The browser handles the unpacking and decoding of the audio data natively and we use the BBC’s Standard Media Player to handle the streaming aspect, ensuring the same full-featured user experience as other BBC services.
We leverage the flexibility of the Audio Factory platform to source the uncompressed feeds in the same way as our other streaming services, then losslessly compress the audio using a cloud-based custom encoding and packaging platform built by BBC R&D.
Do I need any special equipment?
Because the specification for how to do this is so new, only Firefox (51 or greater) on desktop is able to play our stream, but in time we hope other browsers, mobile devices and internet radio manufacturers will follow suit, and we are actively engaging with vendors to make this happen.
You don’t need any special hardware to enjoy our lossless stream – whatever you normally use to enjoy Radio 3 will do.
Note that you’ll need a decent broadband connection – we’d recommend at least 2mbps to avoid buffering.
Any challenges and what were the solutions?
The main challenge was finding a standards-based approach to delivering lossless audio to the browser. Following discussions with technology partners such as internet radio vendors, it was clear that FLAC would be the preferred compression method, but, at the time, there was no specification describing carriage of FLAC in MP4 for MPEG-DASH.
During discussions around other technologies, Mozilla and the Xiph.org Foundation offered to standardise encapsulation in MP4, and this was published on 1st January 2017. Firefox support was implemented ahead of this date, and R&D have built a prototype production workflow based on this specification.
What do you hope to learn from it being on Taster?
We want to find out if our audience can identify audible benefit from lossless streaming and whether that gives a higher quality of experience.
We’d also like to know how and where listeners are accessing the stream, whether via headphones, high-end hi-fi equipment, or even via laptop speakers, and what value they place on the service.
You can help us in our research by taking the questionnaire.
We don’t currently have any plans to provide any permanent lossless services, but the data we gather during the pilot will help inform future service strategy.
A note for Linux users
We have noticed that Firefox binaries distributed by some flavours of Linux are missing a compilation flag required to enable playback of our FLAC stream. If you are having no luck getting the stream to play on your chosen platform, please try downloading an official Mozilla build which we have verified works correctly.
If you'd like to read more about BBC R&D delivering Concert Sound, then why not check out this blog.