BBC on-demand radio streams now at higher quality

The BBC has launched a new 2.0 beta version of the iPlayer, which now has the live and on-demand radio streams built-in alongside the existing iPlayer TV streams. Most importantly, though, the quality of the on-demand radio streams has improved a lot, and there are going to be further improvements over the next few months, including increased bit rates for the live streams later this month. Also, as predicted by this website back in March, the live and on-demand streams are going to switch over to using AAC/AAC+, although this isn't going to happen until later in the year.

On-demand (ex-Listen Again) streams

The on-demand radio streams on the iPlayer beta are now using MP3, and the bit rates have increased significantly:

Although there are more quality improvements still to come (see the 'BBC to stop butchering the audio...' section below), and they don't "sound quite right" at the moment (because the BBC is still butchering the audio), the quality of the on-demand streams have improved a lot in comparison to the diabolical quality provided by the old 64 kbps Real Player Listen Again streams. Once the BBC has made the further quality improvements, the on-demand streams should sound a lot better than via DAB due to MP3 performing far better than MP2 (the codec used on DAB) does at a bit rate of 128 kbps -- MP3 was designed to be used at 128 kbps, whereas MP2 was designed to be used at much higher bit rate levels, which is why 128 kbps MP2 sounds so poor.

Like with the iPlayer TV streams, the radio streams are using Adobe's Flash (FLV) container format to carry the MP3 audio data, and the streams are delivered using Abobe's proprietary RTMP streaming protocol, which stops people from downloading the streams -- it is actually possible to "get at" the audio from a Flash stream, but it's a laborious (and unreliable) process, and the quality is better if you simply recorded the programme when it's broadcast on FM anyway. The second-best way to record BBC radio programmes is to record them off the digital TV platforms, because the BBC's stations use higher bit rates on the digital TV platforms than are used on DAB.

The old Listen Again streams that use the Real Player format will remain available, though, mainly because Wi-Fi Internet radios don't support Flash streaming, and the BBC is currently working with Internet radio manufacturers to provide suitable alternative streams -- which will also be at higher quality than the old Real Player streams.

Live streams

The live radio station streams on the new iPlayer beta are using 64 kbps WMA instead of 64 kbps Real Player. The live streams were already available at 64 kbps WMA beforehand, but WMA has become the primary delivery format.

According to the person in charge of the Internet radio streams at the BBC, James Cridland, who wrote about some of the current and future changes to the streams on the BBC Radio Labs blog, the bit rates for the live streams will be "significantly improved" in July. The blog doesn't mention what the bit rate levels will be, nor whether there would be any change in audio codec (i.e. from WMA to another codec) in July, either.

All of the Wi-Fi Internet radios I'm aware of already support WMA, so there shouldn't be any compatibility problems with the live streams at the moment. But similar to the case with the on-demand streams, once the live streams switch to using Flash with AAC/AAC+ later in the year the BBC is looking to provide alternative streams for Internet radios to receive.

Switching to AAC/AAC+

The BBC has said that both the on-demand and the live streams will switch over to using "the AAC family" later this year -- hopefully by the time they switch over they'll have stopped using the dreadful term "AAC family" and refer to the codecs as AAC/AAC+ like everyone else does.

When the streams switch over to using AAC/AAC+, the BBC has said that the bit rates will be reduced, but that the same "quality will be maintained".

BBC will stop butchering the audio of the Internet streams later this month

As mentioned above, despite the bit rates of the on-demand streams having increased significantly, the streams still don't "sound quite right", which is because the BBC is still 'transcoding' the audio (decoding then re-compressing the audio). The BBC has admitted it is doing this on the BBC Radio Labs blog as follows:

A dirty secret indeed. Transcoding is a major no-no for compressed audio, because it degrades the quality. It is also especially important to avoid transocidng the audio the lower the bit rate of the stream is that's actually distributed to listeners, and Radios 1, 2 and 4 were using a bit rate of just 32 kbps until last year, so it's disgraceful that the BBC has been doing this for so long now.

The reason why the BBC has been doing this for the last six years has been to save the few thousand pounds per year on the cost of using a leased-line (a dedicated data link) to send the radio stations' audio from Broadcasting House to Maidenhead (which is the location that the Internet streams are distributed from). Bearing in mind that people spend 17 million hours PER WEEK listening to the BBC's Internet radio streams, it beggars belief that they couldn't find the few thousand pounds per year to avoid transcoding the audio, especially when they spend over £6 million per year transmitting DAB.

In addition, there has never been any reason to transcode the audio for the Listen Again streams anyway. Whereas the live streams have to be encoded and distributed in 'real-time' as they're live broadcasts (i.e. there can only be a short delay relative to FM), there is no real-time element involved with the on-demand streams, so the audio could have been recorded at Broadcasting House and then sent to be encoded at Maidenhead via the BBC's data network. People wouldn't care less if a programme were added to Listen Again a few minutes later than the time the programme finished at. And yet for the last six years this clearly either hadn't dawned on them that they could do this, or they just couldn't be bothered implementing it. How very kind of them.

Lest we forget

The BBC is already being praised by some quarters for providing these quality improvements, and I think the outrageously bad quality that the BBC's Internet radio streams have been at for the last few years will soon be forgotten. So before we turn the page on this, I don't think we should lose sight of the following, which I explained in detail in the article about the BBC's radio streams in March:

• The BBC has had the opportunity to use the AAC+ audio codec (at zero cost to the BBC) to improve the quality since the codec was adopted for Real Player in January 2004
• The bit rates of the live streams for Radios 1, 2 and 4 were just 32 kbps until last year, even though the cost of Internet bandwidth to content producers such as the BBC falls in-line with Moore's Law (i.e. the cost halves every 18 months or so)
• The BBC has been transcoding the audio for the Internet streams for the last six years, as discussed in a previous section

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