Re: [LAU] Working with netJack2 on raspberry pi

On Tue, April 18, 2017 12:36 pm, Claus Lensbøl wrote: I hope you do not mind, but I have taken the liberty of replying also to the linux-audio mailing list. The question was originally asked there, and many others are more experienced than I with netjack, so keeping replies there is better to get the most accurate information, as well as to benefit others who may have similar questions and search the mailing list archives for possible solutions. I see here a confusion possibly on my part. Your original email stated that you wished to " set up a Raspberry pi as an output for jack" Which is why I asked explicitly: By that do you mean the Rasberry pi has the only audio output? In that case the Rasberry pi should be the master, the Rasberry pi must start jack first with the ALSA driver (assuming R-Pi uses ALSA for the audio hardware, I am not directly familiar with the details of that hardware). After the master (the device with the audio hardware) has started jack successfully then you use jack_load to load the netmanager. That would allow using software on the R-Pi to play audio on your Ubuntu computer. You have configured the R-Pi as a slave of the Ubuntu computer, you do not usually load audioadapter on the slave. Well, I guess that is not entirely accurate. You would not load audioadapter on the slave if you wanted one machine to have audio output, and the other machines to be connected by network to that single audio output. What are you trying to accomplish? Which machine will generate digital audio data, and which machine should output audio? Are you perhaps attempting to have both the local audio device on your Ubuntu computer play audio, and also the R-Pi available to play audio? In that case what you are attempting may be the correct way. If you do not need to use an audio interface on your Ubuntu computer then make it slave only (use net as the driver instead of ALSA, use ALSA as the driver for the R-Pi). Look also at the jackd status messages. I attempted to load audioadapter on a machine where the only audio interface was already in use by jackd and got this on the console where I executed jack_load: $ jack_load audioadapter could not load audioadapter, intclient = 0 status = 0x 1 But also saw these additional messages from jackd: ../linux/alsa/JackAlsaAdapter.h:225, alsa error -16 : Device or resource busy That makes sense on my machine, the audio interface is already exclusively used so audioadapter could not use the device. Perhaps on your R-Pi there are informative messages as well. That previous suggestion was based on the assumption that the Pi was the master since you stated you wanted the Pi to be the audio output. I was assuming that the Pi would be the jack master, since typically in an audio production setup where jack is often used you do not want the audio to be resampled, so you have just one master, a single device with the audio output. Definitely check the output of jackd when using jack_load. Section 6. has this note: By default this client will open the same number of input/output ports the net driver has opened and will use the sampling rate the net backend is currently using. Perhaps the netbackend is using a sampling rate not compatible with the Pi audio hardware. Perhaps there is a mismatch with the number of ports, I do not know from that description if the number of ports on the netjack slave must match the number of physical audio channels available or not. Did you try the suggested: jack_load audioadapter -i "-h" That may give information on the correct number of ports to use. If you really do want to use the audio adapters of both devices (Ubuntu computer and Pi) perhaps zita-net2jack (zita-n2j) will work better for you: http://manpages.ubuntu.com/manpages/xenial/man1/zita-njbridge.1.html -- Chris Caudle