For Radio 3, we offer a very high quality stream at a fixed rate of 320kbit/s for internet listeners, which is a significant saving both in terms of bandwidth and storage compared to the 1.5 Mbit/s original. To reduce the data rate to something more practical for distribution, we have traditionally used a compression codec, AAC, that delivers high quality audio at much lower bitrates. We are taking a raw uncompressed feed of Radio 3 from the BBC’s Audio Factory project and we’ve built a prototype that performs the FLAC encoding and ISOBMFF packaging in the cloud before forwarding the resulting stream to our standard media distribution platform.ĭistributing uncompressed Radio 3 to the home would require bandwidth of around 1.5Mbit/s, considerably more than is typically used even for high quality audio distribution over broadcast or the Internet. This has subsequently been published by Xiph as part of the latest release of FLAC in January 2017. We shared our frustrations with some contacts from Mozilla when they were in London last year, and they kindly agreed to do the standardisation work required. Additionally, without ISOBMFF encapsulation, we’d have to standardise, register and encourage implementation of a new bytestream format for use with the Media Source Extensions. Unfortunately, until recently, there was no way to carry FLAC in a DASH-compliant manner. In reality only ISOBMFF has seen wide adoption, and that is the file format we use to distribute our existing video and audio streams.
Pilot talk 3 flac iso#
MPEG-DASH requires media to be encapsulated using either the ISO Base Media File Format (ISOBMFF), the format that underlies MP4, or MPEG2 Transport Stream.
Pilot talk 3 flac software#
Open, royalty-free and well supported in both software and hardware, FLAC was an obvious choice for compression. Lossless audio is something we’ve been talking about with other parts of the BBC for some time and here at R&D we had been doing some exploratory work around possible formats, but were unable to find a format totally suitable for delivery to the wide range of target devices the BBC serves. We’ve blogged about our work with MPEG-DASH a number of times, and it is our streaming technology of choice on which to innovate. Details below.īBC Taster - Hear the whole BBC Proms 2017 season in High FLAC Fidelity
Pilot talk 3 flac update#
Update - August 2017 - Google Chrome now supports this trial alongside Firefox. This post describes BBC R&D's involvement in bringing this pilot to our audiences. Radio 3 makes considerable investment in music performance and technical excellence, and this pilot enables the most transparent listening experience possible. We've brought together various technologies including MPEG DASH, FLAC compression, HTML5 and the Media Source Extensions to offer you a bit-perfect representation of Radio 3's live output, exactly as it left the studio. In April, BBC Radio 3 and BBC R&D launched what we believe is another world-first for a classical radio network: audio delivered directly to your web browser with completely lossless compression. Research & Development BBC R&D navigation
0 kommentar(er)
