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Open Source DSTAR Voice -- Codec2:

from KE7HQY on June 6, 2010
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The DSTAR protocol is open and freely available, developed by the Japanese Amateur Radio League (JARL). However, the AMBE voice encoding scheme currently used by the DSTAR protocol is not open, rather it is patented by DVSI, Inc.

Development on an open source, freely available alternative to AMBE has been spearheaded by Australian amateur David Rowe, VK5DGR. This open voice codec is called Codec2, and is in a highly experimental stage at this current point. It's advocates include Bruce Perens, K6BP, ( who is well known in open source software circles, and is a huge Free Software advocate.

What's the issue with AMBE?

Codec2 developer David Rowe, VK5DGR talks about this on his blog:


"Due to patents and the amount of confidential information surrounding these codecs (AMBE) I donít think it is possible to make an open codec compatible with these closed codecs. It is however possible to develop a open source, free-as-in-speech codec with similar performance at similar bit rates. [...] A free codec helps a large amount of people and promotes development and innovation"


David Rowe's development site is:

He is currently looking for assistance, either financially or with coding. Because of financial obligations, he's currently on hiatus from development to pay bills with other work. Development milestones and source code are available through his website. David can be contacted at his email: David (at)

A DSTAR protocol implementing Codec2 Digital Voice would significantly drop the entrance level and appeal to a much wider audience. Once Codec2 is stable and competitive, it would offer a real, developed-by-a-ham alternative to the patented AMBE voice encoder.

If you are able to help with development please contact David Rowe!

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Open Source DSTAR Voice -- Codec2:  
by WS4E on June 7, 2010 Mail this to a friend!
>AMBE voice encoding scheme currently used by the DSTAR protocol is not open, rather it is patented by DVSI, Inc.

Hence the reason D-STAR is a loooooooser and will never be successful.

I bet you $20 that Icom will never support this more open codec.
RE: Open Source DSTAR Voice -- Codec2:  
by N4MB on June 9, 2010 Mail this to a friend!
Agreed. Simply compare the number of Echolink nodes to the number of DSTAR nodes at any given time. Echolink offers the VoIP functions of DLINK, essentially for free to the end user amateur on any equipment.

DSTAR is nice in that it is a packaged solution, digital to the end node. Too bad ICOM didn't use technology that could be put in the public domain. That was the strategic marketing mistake.

DSTAR is five years old, ancient in general technology time. Marketing people look at "rate of adoption" to determine the health of a given product. ICOM can't be happy with the results for DSTAR.

If I were ICOM (and were still interested in amateur radio as a marketplace) I'd be formulating an "EchoStar" or "DLink" protocol to combine DSTAR/Echolink/IRLP with a gateway strategy, using modifications to existing radios that use an add-on device for DSTAR. This would enable them to quietly close the book on DSTAR and save face by offering a substitute product offering.

Just my opinion...

Mickey N4MB
RE: Open Source DSTAR Voice -- Codec2:  
by W3JKS on June 9, 2010 Mail this to a friend!
The RETAIL price of one AMBE codec chip is about $25, quantity one, bought from a ham in the Netherlands! It is NOT the huge unreasonable cost that people claim. Compare it to the cost of any comparable codec in small quantities (including the support chips) and you'll see what I mean.

The cost of actually developing a radio product which is only sold in a relatively small market is very real and contributes heavily to the overall cost, unless you're either a hobbyist or a company in business to lose money.

Someone, starting with Mr Perens, needs a lesson on engineering economics and a little less time listening to himself talk.

Good grief.

RE: Open Source DSTAR Voice -- Codec2:  
by K6BP on June 10, 2010 Mail this to a friend!
Sorry you feel that way, John. Actually I have an OK reputation regarding project engineering. You use my code in DD-WRT and a lot of consumer equipment, and I have two wireless chip manufacturers and a supercomputing company paying for advice between today and Monday.

If I were engineering an entire product line and convinced the management that I could eliminate a $5 chip with some software engineering, it would probably be an easy sell. We don't really know what ICOM is paying for AMBE+, but it's probably that much or more.

But the real question is what we do for the future of digial voice. D*STAR is already getting old. First, we need to separate the radio data transport from the voice codec, they are logically separate projects and there is room for a number of data transports, not all of them narrow-band. Regarding voice codecs, there have been a great many free ones, one from Skype, one from Broadcom, the stuff from the Vorbis project, the list goes on. The one Rowe is working on is more specialized for low-band voice radio and is a pretty achievable project, going by what he's done so far.

But whatever we use for a voice codec, it has to be achievable in Open Source as well as proprietary software, because Open Source is a great paradigm for hams themselves to do leading-edge software development that we could never get done with the cooperation of our vendors, and the vendors of finished equipment want to sell it commercially and for non-ham applications without too much expense. Rowe's project fits that bill.

Nobody wants to pay $200 for a box with a little old TI DSP CPU and an old compression algorithm in it. Getting rid of that thing will be a pretty easy sell.

And eventually the folks who manufacture radios want a reason for you to buy a new one. One that has two codecs in it will probably sell pretty well.
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