France adopts DMB for digital radio

France has adopted the DMB system for digital radio, which has got to be one of the most ridiculous decisions imaginable considering that the DAB+ system -- which was standardised early this year -- was designed specifically to solve DAB's problems and, ironically, it was the French broadcasters' decision in 2005 to so strongly oppose using DAB on the grounds that it uses outdated technologies that, in large part, led to DAB+ being designed.

The problem with this decision is that it means that there are now two different upgraded versions of the Eureka 147 DAB system being used for digital radio in Europe, so it threatens to fragment the digital radio market, which will lead to higher receiver prices due to the lower sales volumes for individual receiver models, and it will leave consumers confused about which other countries their receivers will work in -- digital radios bought in the UK won't work in France, and vice versa, although some receivers might work in the other countries.

France has form for sticking two fingers up at the rest of Europe, though, because many years ago it decided to to adopt the SECAM analogue TV standard rather than falling into line with other countries and adopting the PAL analogue TV system.

Why has France adopted DMB?

The big French radio broadcasters claim that they've adopted DMB because it allows them to broadcast pictures or low bit rate video or interactive graphics alongside radio stations to make radio more appealing, and they say that a wider choice of stations doesn't drive people to adopt digital radio.

In reality, they lobbied against DAB+ being adopted, and they're using DMB because it minimises the amount of competition their stations will face on digital radio -- i.e. they've adopted DMB for protectionist reasons. DMB is about 35% less efficient than DAB+, or in other words for a given audio bit rate DMB consumes more capacity, and the visual datastream consumes a considerable amount of capacity as well, so the overall effect is that DMB reduces the number of radio stations that are able to transmit on a multiplex.

The thing that's amazed me is that the CSA, the French communications regulator, fell for their lobbying, because there was absolutely no justification to disallow DAB+ being used alongside DMB, especially as the smaller French radio stations wanted to use DAB+. DAB+ and DMB stations can transmit alongside one another on the same multiplex, and pictures and interactive graphics can be transmitted alongside DAB or DAB+ stations (but not video that's synchronised with the audio), so there was no absolutely reason to stop DAB+ being used. And Ofcom even wrote to the French authorities a couple of months ago criticising them for what it looked like they were planning to do, but clearly it had no effect.

And on the subject of protectionism, when you look at why the UK adopted the old DAB system there's one of two possibilities: (1) that it was simply gross incompetence, and their planning consisted of looking as far as the end of their nose and no further; or (2) they deliberately chose to stick with using DAB because it was so inefficient and its inefficiency allowed the big broadcasters to launch the number of stations they'd like to, but it meant that their stations wouldn't face much new competition.

DAB+ provides much higher audio quality than DMB

The problem with DMB compared to DAB+ from a technical point of view is demonstrated by the figures in the table below, where the figures for DMB are taken from a recent DMB trial in France (pdf), the figures for DAB+ are taken from the DAB+ specification, and where the stations using the respective standards consume exactly the same amount of capacity on a multiplex (the 'sub-channel bit rate'):

Radio stations on DMB have to have a "video" element, and 2 kbps is the minimum bit rate possible. And with a bit rate as low as 2 kbps it would consist of a simple still image being sent every few seconds, which would likely consist of the station logo and that's it -- i.e. a complete waste of capacity, because station logos could be stored permanently in a radio's memory, so they don't need to be transmitted alongside radio stations at all.

So as you can see from the last column of the table, the bit rates available for audio on DAB+ are about 35-40% higher than they are for DMB and, especially at bit rate levels in the sub-100 kbps range using AAC+, an increase in bit rate of 35-40% would translate into DAB+ providing a much higher audio quality than would be provided on DMB.

The audio quality will be much higher than on DAB in the UK

To be fair to the French broadcasters, judging by the bit rate levels they're using with AAC+ (52 - 76 kbps for stereo stations), the audio quality on DMB in France will be much higher than it is on DAB in the UK due to the UK broadcasters using bit rate levels that are far too low to provide good audio quality with the outdated MP2 audio codec that's used on DAB. However, the audio quality on DMB won't be as high as on FM, and the audio quality won't be as high as on typical 128 kbps Internet radio streams either.