[arm-allstar] New Channel Driver Code in Debelopment

[David McAnally]

I believe they use Speex. See these pages.
<https://github.com/sm0svx/svxlink/wiki/FeatureList>
<https://www.speex.org/>

David M.
WD5M


On Fri, Apr 29, 2022 at 10:00 PM "David McGough via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

>
> What CODECs are being used at 16KHz in SVXLink??  Opus?
>
>
> On Fri, 29 Apr 2022, "Patrick Perdue via ARM-allstar" wrote:
>
> > SVXLink operates at 16 kHz.
> >
> > Yes, I can definitely hear a clear difference, even on FM, at least with
> > some radios. Yaesu comes to mind. Those radios tend to cut off closer to
> > 5k than 4, so listening to a Yaesu over SVXLink sounds more like
> > simplex. Granted, I've only actually heard this in recordings of SVXLink
> > demonstrations.
> >
> > With the pervasiveness of Baofengs though, I don't know how many would
> > actually notice if the sampling rate were increased 2x, and the filters
> > adjusted accordingly. Even most analog repeaters I've come across are
> > *at least* as limited as 4 kHz, and usually more. I've heard examples of
> > better, but it's pretty rare now.
> >
> > I say all this as someone who is in favor of using 16 kHz audio as a
> > backbone for FM via VoIP, at least in theory. Most probably wouldn't
> > notice or care, and it would make the most difference when linking
> > well-tuned repeaters together, which is exactly how SVXLink is being
> > used, though I don't think it's very popular in the U.S. for that
> > application.
> >
> > HamVoIP does support G.722, but I think this is mostly for compatibility
> > reasons, and won't actually do anything to increase the frequency
> > response when using radios due to a well-done implementation of low
> > pass/anti-aliasing on the simpleusb driver, among other things. Having
> > used ASL, which doesn't have as good implementation in comparison, I
> > definitely do appreciate that. Maybe if everyone is on a VoIP phone set
> > to G.722, you'd notice.
> >
> >
> > On 4/29/2022 5:37 PM, "M Lech via ARM-allstar" wrote:
> > > While we're at it, can we implement 16KHz sampling instead of the
> crummy
> > > 8KHz sampling ? I'd think I'd died & went to heaven to have the audio
> > > bandwidth matching our RF links. For me this is huge. The hardware has
> no
> > > problem doing it, so why don't we? Thanks in advance!
> > >
> > > 73,
> > > Matt W6XC
> > >
> > > On Fri, Apr 29, 2022 at 9:27 AM "Dave Petrie via ARM-allstar" <
> > > arm-allstar at hamvoip.org> wrote:
> > >
> > >> Hi David, just curious if you made any progress with the new channel
> driver
> > >> code in development so that chan_simpleusb can send and receive CTCSS
> like
> > >> usbradio does. Here is what I found that led me to ask the question.
> > >>
> > >> On 9/5/21 11:41 PM, David McGough wrote:
> > >>
> > >> Hi Jim,
> > >>
> > >> CTCSS generation isn't currently in the chan_simpleusb code. However,
> it
> > >> is in new channel driver code in development.
> > >>
> > >> All the original usbradio related code and features are in HamVoIP.
> So,
> > >> that should work, if you can tolerate the sporadically glitchy
> sounding
> > >> audio.
> > >>
> > >> How quickly do you need this?  I can probably get you info on the new
> > >> channel driver in a few days.
> > >>
> > >>
> > >> 73, David KB4FXC
> > >> _______________________________________________
> > >>
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> > >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >>
> > >> Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > >>
> > > _______________________________________________
> > >
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> > >
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> > _______________________________________________
> >
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> >
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> >
>
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