[arm-allstar] software update status

[kk6ecm]

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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> 
> 
> 
> -- 
> --
> Tim
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