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Audio Factory overview: update

Andrew Scott

General Manager

Following the very large number of comments on my previous post I wanted to provide a clear summary and address some of the common questions.

What has happened?

1) The Audio Factory team have built a new system for encoding and creating our audio streams online. This system supports both the BBC iPlayer Radio and syndication partners (other organisations to whom we provide our streams)

2) The new system supports the following formats for syndication:

Live = HLS/AAC and SHOUTcast/MP3

On demand = HLS/AAC

Podcasts = MP3 (file or progressive download, not streamed)

If you are using any other format, please expect it to stop.

3) We have migrated all BBC maintained clients to the new streams

4) We are continuing to work with our syndication partners, including manufacturers and their technology partners, to help them distribute and consume the new formats. Expect announcements from them as status changes.

5) We are continuing to work on bringing the UK only version of the live streams to SHOUTcast/MP3, particularly for Internet radios. The UK streams contain sports commentary and live music events that are blocked to international users because of rights restrictions.

6) The old systems that generated WMA, RTMP and other formats have now been switched off.

7) We are continuing to work with BBC R&D and the industry to define an agreed configuration for MPEG DASH so that we can introduce that service (in addition to HLS/AAC) as soon as possible.

Why can’t the BBC tell us about specific devices?

The way that the BBC’s syndicated streams, along with those of other broadcasters, are made available to Internet Radios and other audio devices involves a number of organisations in a moderately complex arrangement. A simplified view of this includes:

A number of organisations, called aggregators, who fetch data about available audio services from the BBC and other broadcasters and make that information available to chipset and device manufacturers

A number of chipset manufacturers who provide hardware and software that can read the information provided by the aggregators and use that to find and consume the appropriate audio services

A number of device manufacturers who design and build devices for users

Some organisations operate in more than one of these categories:

Given the wide range of organisations involved we are not able to provide any details about the status of any specific equipment. We have already seen announcements from some that they have migrated to our new streams, and we expect more to come.

What about community maintained services?

Some devices are currently being supported by the community of listeners.

It is difficult to support individuals, rather than businesses. I'm aware of the level of pressure and responsibility which these individuals take on to aid a group of people. We are actively looking at some options to see if it is possible to provide support to these community maintained services on a sustainable basis.


We have seen a number of issues reported recently where some devices are reporting errors when users try to access Podcasts. The devices in question are perfectly capable of consuming the MP3 Podcast files, we are creating the MP3 files in the same format as before, and the information about the Podcasts is still being published in the same format as before, so at this stage we are working with the manufacturers to get to the bottom of this problem and how best to resolve it.

Why have the RTMP Streams gone?

Users of some devices were disappointed that the on demand RTMP streams were removed. We have never published those streams as “syndicated” streams, i.e. ones that are explicitly available for aggregators and manufacturers to use.

We had migrated all of our internal clients off those streams, but it turns out that people have reverse engineered these streams, and were using them in ways that are not supported, which is against the terms under which they are provided.

One significant part of what we are trying to do here is get everyone onto a common set of streams so that we can support them and manage changes. I’m sorry I wasn’t able to be clear about when this was going to happen when I posted last week, but the team working on the change are also making a large number of other changes so it was hard to predict exactly when they were going to get to the RTMP streams and they got there sooner than I thought.

What drove these decisions?

HTTP chunking is an efficient way of delivering audio at scale. The license fee has been frozen for a number of years now, which means our available budget actually reduces every year with inflation. Alongside this demand for our services increases every year. We therefore have to find a cost effective way of delivering our streams.

HTTP chunking allows us to deliver new features such as DRM Downloads and live rewind. We believe these will significantly improve the online listening experience for users of mobile devices and all devices respectively.

HLS is the most widely adopted implementation of HTTP chunking at this time. MPEG Dash is fast approaching. We are therefore using HLS now, and will add MPEG Dash as soon as possible.

In the mean time we continue to provide SHOUTcast streams for devices that can’t consume HTTP chunked streams yet

Other questions:

1) Some users are not happy about the quality of the SHOUTcast/MP3 live streams at 128kbps

We are continuing to monitor the reliability of these streams and address any issues. At this stage we have no plans to increase the MP3 bitrate.

2) Some people are not happy that they can only receive Podcasts, not the full range of on demand programmes via their device.

Podcasts are available to download without any protection. All other content we have to protect on behalf of the rights holders. Since we have switched off WMA we can’t do this in a format which all devices can consume.

3) Some people are not happy that we haven’t committed to supporting SHOUTcast for longer than the 12-24 months we have already stated

We are still working with the manufacturers and their technology partners on their adoption of the new streams. We will not be making any further decisions on SHOUTcast streams until that process has progressed further.

4) Some people are not happy that we haven’t published the stream URLs

We have no plans to release the stream URLs because we know that we are going to have to change them at some point in the future and need to be able to manage the changes.

I apologise for any inconvenience these changes have caused, and I will be happy to respond to comments, particularly those which raise new points I have not addressed in this post, my previous posts or my previous comments.

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