Brian Morrison wrote:
On 24 Sep 2010 09:42:02 GMT
Rob wrote:

Brian Morrison wrote:
With D-STAR unless you buy the pre-programmed DSP chips or the DV
dongle you can't legally reimplement the AMBE codec at all, and that
makes it very different from other kit that implements unpatented
modes.

The problem is that amateurs cannot live with the fact that someone
implemented a codec that is better than what they can develop
themselves.

Really? I thought that what those of us that can't live with it thought
is that we don't like technology that locks out homebrew. That's what
the use of DVSI's AMBE codec does.

Not really. You can buy the chip that implements AMBE and use it
as part of a homebrew design.
That is really not much different from buying a power transistor to
get 100 Watts of output from your homebrew transceiver instead of
developing your own, or making your own transmitter tube.
Everyone chooses their own level of components to work from. Some
build the microcontroller for their transceivers from a Z-80, an
EPROM, a CMOS RAM and some LSTTL logic. Others use an integrated
microcontroller with everything on a chip. Still others buy a small
board with a functioning computer system on it and use it as part of
their transceiver.

I don't know exactly why JARL chose AMBE other than because it was the
only codec available at the time. If so, they should have thought about
that a lot harder and perhaps decided to sponsor the development of a
free codec instead. That would have been really good, but I suppose I
can see that it would have introduced a delay. D-STAR has other faults,
one being that it appears not to be extensible so that there is no way
to include other codecs and allow the correct one to be used according
to the other user's set up.

When the chose AMBE there really was no alternative. And even today,
you will not be able to find an open codec that offers speech quality
at the bitrate and bit error resilience that the AMBE codec does.

It is very easy to write "then lets develop that" and apparently much
harder to actually do so.

W.r.t. extensibility, it would sure be nice if codecs could be negotiated
and an alternative could be added, but it would not bring much to
D-STAR as there still would be different worlds of users that cannot
talk to eachother (those with the commercial Icom transceivers that
have AMBE and nothing else, and those with the homebrew transceivers
with open codec and no AMBE).

There would be no problem when amateurs could actually develop a
better codec than AMBE. But they have not shown they can.

Well we'll see won't we? It's taken a while to find people with the
necessary expertise but Codec2 is now moving forward with people
working on it that have that expertise.

Given enough time, it could be that something is developed that is
open and does not violate patents. But I think it will take a lot
of time and there is little chance that at the end of this development
there is still a userbase left that wants to buy and use products
based on it.

Sometimes is it better to just admit that someone did a better job
than you could have done yourself, and just pay him for the work.

I have no problem with that, remember that the "free" part of free
software is referring to freedom, not money. But if someone refuses to
provide something that I can look inside and understand then I won't
use it.

It's called a choice.

That is your choice. But that does not mean that others are wrong.

"Rob" wrote in message
...

use it.

It's called a choice.

That is your choice. But that does not mean that others are wrong

Oh dear Rob, you must be new here! While what you say is, of course,
correct it isn't accepted by bigots.

If half of those who are so "anti" DStar got on an developed an alternative
CODEC (and it is just the CODEC which is proprietary), this debate would
have ended long ago. As it is, by the time the alternate CODEC becomes
viable, I fully expect that such systems will be so "yesterday".

Amateur radio has many facets, DStar is simply one of them. Why can't people
be left to enjoy their pet facets while others get on and enjoy theirs?

--
73
Brian G8OSN/W8OSN
www.g8osn.net

On 24/09/2010 17:22, Brian Reay wrote:

Amateur radio has many facets, DStar is simply one of them. Why can't people
be left to enjoy their pet facets while others get on and enjoy theirs?


Because D-Star isn't amateur radio.

There is no experimentation involved, and can't be.

Yeti wrote:
On 24/09/2010 17:22, Brian Reay wrote:

Amateur radio has many facets, DStar is simply one of them. Why can't people
be left to enjoy their pet facets while others get on and enjoy theirs?


Because D-Star isn't amateur radio.

There is no experimentation involved, and can't be.

Over here it is probably the mode with the most experimentation going
on in ham radio today...

Of couse not with the codec.
But in any communication system there are things that cannot be changed
or incompatability would result.
That does not mean there cannot be experiments elsewhere in the system,
or in the application of the system as a whole.

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time. It was very clear that
a couple of critical mistakes were made in the design, and there were
proposals on how to fix them, but they never took off as it simply
wasn't practical to change AX.25
It really made no difference if it was open or closed, it was unchangable
anyway.

Yet, amateurs used it as a black-box building block in many applications
and experimented a lot with it.

On 24 Sep 2010 16:34:08 GMT
Rob wrote:

Yeti wrote:
On 24/09/2010 17:22, Brian Reay wrote:

Amateur radio has many facets, DStar is simply one of them. Why
can't people be left to enjoy their pet facets while others get on
and enjoy theirs?


Because D-Star isn't amateur radio.

There is no experimentation involved, and can't be.

Over here it is probably the mode with the most experimentation going
on in ham radio today...

Of couse not with the codec.
But in any communication system there are things that cannot be
changed or incompatability would result.
That does not mean there cannot be experiments elsewhere in the
system, or in the application of the system as a whole.

Remember packet. The AX.25 protocol was open, but it could not
really be changed because that would break compatability between the
many implementations that existed after some time. It was very
clear that a couple of critical mistakes were made in the design, and
there were proposals on how to fix them, but they never took off as
it simply wasn't practical to change AX.25
It really made no difference if it was open or closed, it was
unchangable anyway.

Yet, amateurs used it as a black-box building block in many
applications and experimented a lot with it.

And ultimately it failed (what's left of the packet network is a shadow
of what it was) because of that lack of flexibility.

Amateur radio has a difficult-to-overcome problem in that we always
build systems from the bottom up and don't design in the features that
allow growth and variation. D-STAR is another example of a system that
shares that same fault.

I hope that it's possible to create something that doesn't have these
limitations, provides better function and allows more experimentation
with all aspects of the technology.

--

Brian Morrison

"Rob" wrote in message
...

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will be
limited- unless they only want to talk to themselves or with others they've
co-ordinated experiments with.

--
73
Brian G8OSN/W8OSN
www.g8osn.net

On Fri, 24 Sep 2010 18:08:15 +0100
"Brian Reay" wrote:

"Rob" wrote in message
...

Remember packet. The AX.25 protocol was open, but it could not
really be changed because that would break compatability between
the many implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will
be limited- unless they only want to talk to themselves or with
others they've co-ordinated experiments with.


Well the plan is that eventually any closed system becomes out evolved,
so the advantages of the open alternative become available to all. I am
more than happy to share, DVSI are not.

--

Brian Morrison

In article ,
Brian Reay wrote:

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will be
limited- unless they only want to talk to themselves or with others they've
co-ordinated experiments with.

Seems to me there's plenty of opportunity for flexibility with regards
to codecs. The protocol could be designed to allow for negotiation of
a common codec between two radios - start out with a simple
"universal" codec to get the communication started, and then
optionally switch to a different one.

Something like this is done in the commonest voice-over-IP protocol
family (SIP). There are numerous codecs available, ranging from
bog-standard telephony-style (uLaw and aLaw), to simple linear PCM, to
ADPCM, to various forms of sophisticated coding and compression. Some
of these require paid licenses (e.g. G729), some come with a
commercial- but-free license (e.g. ILBC), some are based on patents
which have now expired and can be implemented freely (e.g. versions of
GSM), and some are aggressively open-source and free-as-in-
speech-and-beer (e.g. Speex).

Protocol negotiation becomes tricker when you're dealing with a
repeater system, or a more-than-two-way simplex conversation, but
that's where the fun and experimentation comes in!

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Fri, 24 Sep 2010 10:42:10 -0700
(Dave Platt) wrote:

Seems to me there's plenty of opportunity for flexibility with regards
to codecs. The protocol could be designed to allow for negotiation of
a common codec between two radios - start out with a simple
"universal" codec to get the communication started, and then
optionally switch to a different one.

Yes, that's what's wanted, but the current D-STAR implementation
appears to have no flexibility to do this and there are no version
fields in the frame structure so it can't be made backwards compatible.
The design ought to have had this built in, but seems not to have
considered doing it.

--

Brian Morrison

On 24/09/2010 18:08, Brian Reay wrote:
wrote in message
...

Remember packet. The AX.25 protocol was open, but it could not really be
changed because that would break compatability between the many
implementations that existed after some time.

Which is something the "anti" AMBE CODEC people ignore.

If the open CODEC happens, their scope to "experiment" with it will be
limited- unless they only want to talk to themselves or with others they've
co-ordinated experiments with.


In this case, you can always re-flash the chip containing your chosen
version of the codec.

Something very few had the capability to do back in the days when packet
was a big thing, and something you're expressely forbidden to do
(indeed, prevented from doing) with an AMBE DSP chip.