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Thread: Codec2 - Open Source DSTAR Digital Voice

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  1. #1
    Join Date
    Jul 2006
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    Montana
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    Default Codec2 - Open Source DSTAR Digital Voice

    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, (www.codec2.org) 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: http://www.rowetel.com/blog/?p=128
    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: www.rowetel.com/ucasterisk/codec2.html

    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) rowetel.com

    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!

  2. #2
    Join Date
    Sep 2005
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    London
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    Default Open source DSTAR voice - Codec2

    Open source DSTAR voice - Codec2

    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, (www.codec2.org) 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: http://www.rowetel.com/blog/?p=128

    "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: www.rowetel.com/ucasterisk/codec2.html

    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) rowetel.com

    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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  3. #3

    Default

    D-Star will go the way of Packet. Give it time, codec or no codec.

    K2WH

  4. #4
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    Default

    If not....it won't last for long...

  5. #5
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    In Missouri Ozark Mountains
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    Default

    D-Star adds many new users every day all around the world and more and more. On most days I work 8-12 different countries in the morning people I know on a first name basis and hams from most states. I am an avid DXer and spend most all of my time on HF but when bands are dead will work some D-Star none logged.

    Some states have went to D-Star for state wide ecomm and more are looking to switch to the more secure system.
    73 de Fred N0AZZ

    _____________________________________

    The License is Only Your Starting Point in Radio!
    MVDX/CC of SW MO., DX Hogs, OARS, NARC, NCDXF
    ARRL member, ARRL and W5YI VE
    DX the thrill of the chase

    ""D-STAR making use of the 2/ 440m repeaters for real world Digital Voice usage around town and around the world""

    " Not one of us can do what all of us can do " ** Max Lucado

  6. #6
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    Exclamation

    How would Codec2 be best implemented? Joel Koltner, KE7CDV offers this brilliant tidbit from the Dstar_digital yahoo group:

    most hams operate D*Star through repeaters anyway, one approach here would be to have the *repeater* have both AMBE and CODEC2 (or whatever) capabilities, and just translate between them on-the-fly. (This approach is used with public service radio systems, since there lots of different companies decided to build their own proprietary protocols and used different CODECs as well.) I would wager that repeater usage probably accounts for more than 90% of D*Star voice traffic, and getting repeater builders to incorporate a backwards compatible radio into their system (that has the same interface as the current Icom boxes) is nowhere near as daunting as getting everyone with an HT or mobile D*Star rig to buy something new.

    The repeater could seamlessly translate to and from existing the D*Star gateway to both codecs!

  7. #7
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    Default

    Quote Originally Posted by N0AZZ View Post
    D-Star adds many new users every day all around the world and more and more. On most days I work 8-12 different countries in the morning people I know on a first name basis and hams from most states. I am an avid DXer and spend most all of my time on HF but when bands are dead will work some D-Star none logged.

    Some states have went to D-Star for state wide ecomm and more are looking to switch to the more secure system.
    A Codec2/AMBE repeater would allow both ICOM DSTAR owners access AND *free* experimentation with Codec2 using existing FM radios and Smartphones/netbooks/laptops/etc.

    I think hams have become senile with the proprietary codec, and asssume "its here, that's the way it should be and will always be". Sure, ICOM's radios and the DSTAR protocol itself dictate AMBE codec use. However, a open source codec allows infinite latitude to experimenters in software installations and inexpensive (FREE) soundcared etc etc *without* the need for a hardware chip layer.
    Last edited by KE7HQY; 06-07-2010 at 05:28 PM.

  8. #8
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    Default

    If anything, supporting Codec2 development would add to the existing DSTAR pool of users...

    It would drop the bar from a $200 DV dongle to a free implementation - and I know most hams would go for a free implementation

    How would they access the DSTAR gateway? Through a Codec2-compatible DSTAR repeater or node - it would exponentially add more users to the existing DSTAR user base!

  9. #9

    Thumbs down End of ham radio?

    I worked on the early development of digital voice comms in the 70's. I was involved in the military/secure telephone comms including the design of the DSVT and the DNVT. I know what LPC is and what it isn't. But it is not in the best interest of Ham radio to have a secret digitization code for voice comms.
    Ham radio is supposed to be an "open" forum of users of all types of radios and manufacturers. In order to use "DStar", you are being held captive by the manufacturer of the codec and by the licensed radio producer. Now we are purporting to have a "secret" society of "secure" radio communications - sounds like we are in the ICOM military. This is not ham radio as I used to know it. What is happening to society?

  10. #10
    Join Date
    Jan 2000
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    Oklahoma City
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    988

    Default

    Quote Originally Posted by N3CRM View Post
    What is happening to society?
    Over-population.

    Before you can use Spread Spectrum, you have to digitize the audio. That's what my cell phone does :-)

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