Re: [Jack-Devel] How to setup jack for transmission of audio from embedded system to jack equipped audio workstation?

Yes, indeed, I have got it running, but in fact i'm not fully
satisfied with achieved latency.
In fact I thinkthere may be a need for a dedicated solution, due to
following requirements:

1. It is supposed to be a wireless guitar system, so the embedded system must
   be connected via WiFi.
 2. UDP over WiFi will almost for sure result in lost packets (due to
collisions),
    so I need a protocol with acknowledge (RUDP, UDP-RT or simply TCP/IP?)
3. At the transmitter side there is no need for buffering at all. I
should simply
    transmit all samples received from the ALSA driver as quickly as they come.
    The buffering and synchronization should be done only on a receiver side.

So I think, that the best way to go will be to modify the existing
alsa_in program so that it receives samples via network...

Thanks & Regards,

Wojtek

On Sat, Oct 26, 2013 at 11:29 AM, raf <[hidden]> wrote:
> hello,
>
> you're close to having it work.
>
> The config on your workstation looks ok, the problem is on the embedded side.
>
> On the embedded system, you have to start jack with the "net" backend, not the alsa one.
> jackd -R -d net  (more option available)
> Doing this, the embedded system will look for a master jack which is started on the workstation, and create the ports for audio communication.
>
> Then to have the signal of your guitar go through the network link, you have to use jack_load audioadapter on the embedded system to gain access to the soundcard.
>
> A lot more information on this page, will help you understand better this configuration :
> http://trac.jackaudio.org/wiki/WalkThrough/User/NetJack2
>
> I have tried a similar setup, and it's working great ! Good luck
>
> Raphaël
>
> Le 26 oct. 2013 à 00:05, Wojciech Zabołotny a écrit :
>
>> Hi,
>>
>> I'm preparing a jack based wireless guitar system.
>> The previous solution was based on microcontroller,
>> dedicated radio link and receiver imitating USB audio card
>> ( http://www.ise.pw.edu.pl/~wzab/wireless_guitar_system/ ).
>> In this solution I used "alsa_in" to synchronize the input stream
>> with the soundcard in the receiving audio workstation.
>>
>> Upgrading my system I have decided to replace the microcontroller
>> based transmitter with dedicated radion link with an embedded system
>> equipped with the WiFi card, and use standard WiFi card as the
>> receiver in the audio workstation.
>>
>> I have successfully implemented the driver for CS5343/4 ADC for the
>> ALSA SoC and packaged the jack2 for Buildroot.
>> ( https://groups.google.com/forum/#!topic/comp.sys.raspberry-pi/EgQAQ0DNwN4 ,
>>  http://lists.busybox.net/pipermail/buildroot/2013-October/081087.html ),
>> so now I only need to integrate jack in the embedded system with jack in the
>> workstation.
>>
>> And here I run into real problems.
>> I'd like to have the audio workstation initialized in such a way, that
>> jack is running, audio processing programs are also running and connected
>> to jack, and the system waits for connection of the embedded system
>> as an audio source.
>> So I have started jack with qjackctl on my workstation. Then I should to
>> create the audio input ports associated with the network server waiting
>> for data stream coming from my embedded system. However I couldn't find
>> any way to do it :-(.
>> I've tried "jack_load netmanager", but it didn't create any ports.
>> Adding the "-c" option didn't help
>> (load netmanager -i "-c").
>> So I've tried to run "jack netadapter", and it created additional
>> capture ports.
>> But now it is unclear for me, how to connect to it from my embedded system,
>> because it seems, that now my audio workstation should be the slave...
>>
>> When I start jack in my embedded system:
>> jackd -P41 -p512 -t10000 -dalsa -r48000 -p256 -n2 -Xseq  -Chw:0,0
>> jack_load netmanager -i "-c"
>>
>> Nothing happens in the workstation. In the jack message window I can still see:
>> Ringbuffer automatic adaptative mode size = 1024 frames
>> NetAdapter started in sync mode without Master's transport sync.
>> Waiting for a master...
>>
>> I don't know, is it possible to setup such a system with workstation
>> waiting for connection of the embedded system?
>> Should I use another protocol - e.g. netone?
>> Should I write my own application imitating "alsa_in" but using
>> the network connection?
>>
>> I'll appreciate any suggestions, explanantions or hints.
>>
>> TIA & Regards,
>> Wojtek
>>
>>
>>
>>
>> "jack_load netmanager" on it.
>>
>> 
>> Jack-Devel mailing list
>> [hidden]
>> http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
>

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