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Assorted ramblings from the developer

DRM in SDR Console

I'm often asked to incorporate a Digital Radio Mondiale (DRM) receiver into SDR Console. The reasons why I haven't done this are:

  1. Patent / royalty issues with the audio codec, and
  2. The Dream project works well.

Brendan Wahl, WA7HL, co-Moderator, of the DRM North America Newsgroup explained the lagal minefiled recently. The text below is reproduced with his permission.

Hi all, got some background here for you. I've been following DRM since the beginning,  and still admire it for its broadcast quality and capabilities.

The DRM system was originally written by the Frauenhofer Institute in Germany, with the first software for personal use requiring a license key that cost the individual listener somewhere around ~€49/$49. I've got one somewhere, but I haven't had to use it since the freeware "DReaM" came out. No key needed when using that software package, which is still available on Github IIRC. The original commercial software still works, but it's very simple and doesn't provide a lot of bells and whistles. I'm not sure it's available anymore.

What happened was that the AAC codec (and it's variants, esp. XE-AAC...) was developed some years after the receiving software was first published with older codecs already available freely. The Frauenhofer Institute in the meantime had sold its work and code already done on that codec to Dolby Inc., who didn't want to give anything away. Hobbyists went from being able to receive all codec forms of broadcast DRM with little to no cost, to technically having to remove the FAAD.DLL file and receiving nothing, period. Since all DRM broadcasters switched to the XE-AAC codec due to it's efficiencies, hobbyists got left out in the cold with that shift. That .DLL file has been known to circulate privately, since even Dolby admitted that trying to get people to delete a file that they already had was like screaming in the wind.

Currently, as I understand it and as Simon indicates, radio manufacturers and developers must pay a license fee upfront to use the now-Dolby owned codecs. The listeners no longer have to pay, but the commercial party 'pays' on their behalf. This would include Simon of course, since he is both a commercial and hobbyist software developer, working as one entity.

Simply put, DRM is a minefield for someone like Simon. It's not only a bit of a coding time-suck, the potential legal exposure is horrible. It is a big enough issue that most radio manufacturers are simply avoiding the whole issue by not making DRM capable receivers. A Chinese manufacturer, Gospell, and a couple of Indian companies have stuck their financial necks out for DRM, since it is being introduced in both countries, but actual production of quality consumer equipment has been difficult, to say the least.

I should note that SDRC works wonderfully with the DReaM software being fed via a virtual cable. Was listening to Radio New Zealand International just the other night while they were doing some DRM testing, had perfect reception using my HF+. Can't wait for my Discovery to get here!

I'll back Simon on his choice of not including DRM. I use SDRC more than any other radio software, and I appreciate all of his his hard, SOLO, work on it. No wonder he needs our beer money...and of course, the canine is always hungry. I know, I have one too.

Brendan WA7HL
Co-Moderator, DRM North America Newsgroup

So there you have it. Thanks Brendan. If you want to listen to DRM use Dream and a virtual audio cable.


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