[arm-allstar] software update status

[David McGough]

Bob,

While it happens rarely, I have heard these audio delays on usbradio,
running on a fast PC's as well.

Faster hardware clearly hides this issue better, as would be expected.

73, David KB4FXC




On Tue, 1 Sep 2015, kk6ecm wrote:

> Is this an issue with usbradio on ACID (higher throughput burden) as well?
> 
> Thanks,
> Bob
> kk6ecm
> 
> Sent from iPad
> 
> 
> > On Sep 1, 2015, at 1:01 PM, Tim Sawyer <tisawyer at gmail.com> wrote:
> > 
> > David,
> > 
> > Sounds like you've found the root cause of this and have a fix is the works.
> > 
> > Excellent!
> > 
> > I think this same problem is happening with RTCM's as well. I does seem less frequent or harder to detect by ear. That may have more to do with using ACID on Intel Atom hardware than it does with RTCM's, don't know. 
> > 
> > Is your fix only to simpleUSB, or is there a chance it will help RTCM's as well? 
> > 
> >> On Mon, Aug 31, 2015 at 11:24 PM, David McGough <kb4fxc at inttek.net> wrote:
> >> 
> >> Hi Bob,
> >> 
> >> The variable audio delay issue is occasionally seen on PC-computer
> >> platforms, too, particularly with the simpleusb driver. This is NOT the
> >> audio delay that is unavoidable due to buffering as the audio samples pass
> >> through Asterisk. Nor is this issue related to the Asterisk jitter buffer,
> >> etc.
> >> 
> >> Basically stated, the problem is that the input sample rate -dynamically-
> >> varies from the output sample rate. Depending on various factors, you may
> >> have too many samples, or too few, at any given moment. With the current
> >> code, the main issue seen is that too many output sound frames get queued,
> >> causing a frequently increasing in length input to output audio
> >> delay--sometimes with delays of maybe as much as one second (really
> >> annoying!). If there is an output buffer under-run, you hear a pop/click
> >> due to running out of samples.
> >> 
> >> Initially, I suspected some kind of subtle bug in the simpleusb sound
> >> code. But, after experimentation, I've been able to easily duplicate this
> >> issue using my native ALSA stand-alone test software or even ALSA
> >> applications like arecord and aplay, etc.
> >> 
> >> One solution to this problem is to use a dynamic buffer that effectively
> >> re-samples the audio, gently up-sampling or down-sampling, depending on
> >> the current trends for overrun or under-run.  I've got working software
> >> that accomplishes this now. And, it runs full-duplex beautifully for 24+
> >> hours with no change in audio delay and no logged clicks or pops.
> >> 
> >> Hopefully, I'll get a few days time when I'm rested to focus on completing
> >> the integration of this code into simpleusb.  So far, I've had no time at
> >> all to complete this.
> >> 
> >> But, hopefully soon.
> >> 
> >> 73, David KB4FXC
> >> 
> >> 
> >> 
> >> On Mon, 31 Aug 2015, kk6ecm wrote:
> >> 
> >> > Couple of questions:
> >> >
> >> > 1) Is this audio delay the same as experienced with ACID?
> >> >
> >> > 2) What is the nature of the fix that reduces the delay?
> >> >
> >> > Thanks,
> >> > Bob
> >> > kk6ecm
> >> >
> >> > Sent from iPad
> >> >
> >> >
> >> > > On Aug 27, 2015, at 9:33 AM, David McGough <kb4fxc at inttek.net> wrote:
> >> > >
> >> > >
> >> > > Hi LaRoy,
> >> > >
> >> > > Progress has been slow in recent weeks, due primarily to family
> >> > > commitments that I've got. At this point, the update is waiting on me.
> >> > >
> >> > > I am hopeful to minimally have a bug-fix interim release soon. The big
> >> > > item on the list being resolution for the variable audio delay.
> >> > >
> >> > > I hope to have more details soon.
> >> > >
> >> > >
> >> > > 73, David KB4FXC
> >> > >
> >> > >
> >> > >
> >> > >> On Thu, 27 Aug 2015, LaRoy McCann wrote:
> >> > >>
> >> > >> Doug,
> >> > >> Just curious on how things are progressing with a new software update
> >> > >> for the PI2?
> >> > >>
> >> > >> Thanks,
> >> > >>
> >> > >> LaRoy McCann, K5TW
> >> > >>
> >> > >>
> >> > >>
> >> > >>
> >> > >> ---
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> >> > >>
> >> > >> _______________________________________________
> >> > >>
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> >> > >>
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> >> > >
> >> > > _______________________________________________
> >> > >
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> >> > >
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> >> > _______________________________________________
> >> >
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> >> >
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> >> >
> >> 
> >> _______________________________________________
> >> 
> >> arm-allstar mailing list
> >> arm-allstar at hamvoip.org
> >> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >> 
> >> Visit the BBB and RPi2 web page - http://hamvoip.org
> > 
> > 
> > 
> > -- 
> > --
> > Tim
> > _______________________________________________
> > 
> > arm-allstar mailing list
> > arm-allstar at hamvoip.org
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> > 
> > Visit the BBB and RPi2 web page - http://hamvoip.org
>