Hi,

For some reason if I have PD open then I can't hear any sound from chrome (or use my microphone). However, if I start chrome first, then I can't hear any sound coming out of PD (and I assume I can't use the microphone to input to pd either).

Error:
ALSA output error (snd_pcm_open): Device or resource busy#

Linux and audio can get relatively hairy,.. basically if you try to use ALSA directly with Pd, you can't use anything else that has sound. That's where intermediary layers like PulseAudio and JACK come into play that talk to ALSA, PulseAudio is good for general use, JACK is good for lower-latency stuff like you would want with Pd so use JACK with Pd and then you want to download "sinks" where everything else can use PulseAudio and then be connected to JACK, I have this info saved somewhere...

Edit: Well essentially you want to sudo apt install both qjackctl (which I think installs jack also?) and pulseaudio-module-jack. Then in qjackctl: under setup > options: "pulseaudio -k" on startup, "pacmd load-module module-jack-source channels=2; pacmd load-module module-jack-sink channels=2;" after startup, then "pulseaudio -k" after shutdown. Basically, kill the pulseaudio process when you startup and after you shutdown the JACK server. You might have to tinker with /etc/pulse/default.pa,.. can't remember if I did on my current installation but we'll get to that if need be...

I found this solution and it worked

@sdaau_ml said:

Sorry to necro this thread, but I finally found out how to run PureData under Pulseaudio (which otherwise results with "ALSA output error (snd_pcm_open): Device or resource busy").

First of all, run:

pd -alsa -listdev

PD will start, and in the message window you'll see:

audio input devices:
1. HDA Intel PCH (hardware)
2. HDA Intel PCH (plug-in)
audio output devices:
1. HDA Intel PCH (hardware)
2. HDA Intel PCH (plug-in)
API number 1

no midi input devices found
no midi output devices found

... or something similar.

Now, let's add the pulse ALSA device, and run -listdev again:

pd -alsa -alsaadd pulse -listdev

The output is now:

audio input devices:
1. HDA Intel PCH (hardware)
2. HDA Intel PCH (plug-in)
3. pulse
audio output devices:
1. HDA Intel PCH (hardware)
2. HDA Intel PCH (plug-in)
3. pulse
API number 1

no midi input devices found
no midi output devices found

Notice, how from the original two ALSA devices, now we got three - where the third one is pulse!

Now, the only thing we want to do, is that at startup (so, via the command line), we set pd to run in ALSA mode, we add the pulse ALSA device, and then we choose the third (3) device (which is to say, pulse) as the audio output device - and the command line argument for that in pd is -audiooutdev:

pd -alsa -alsaadd pulse -audiooutdev 3 ~/Desktop/mypatch.pd

Yup, now when you enable DSP, the patch mypatch.pd should play through Pulseaudio, which means it will play (and mix) with other applications that may be playing sound at the time! You can confirm that the correct output device has been selected from the command line, if you open Media/Audio Settings... once pd starts:

As the screenshot shows, now "Output device 1" is set to "pulse", which is what we needed.

Hope this helps someone!

EDIT: I had also done changes to /etc/pulse/default.pa as per https://wiki.archlinux.org/index.php/PulseAudio#ALSA.2Fdmix_without_grabbing_hardware_device beforehand, not sure whether that makes a difference or not (in any case, trying to add dmix as a PD device and playing through it, doesn't work on my Ubuntu 14.04)

However after exiting the program and opening it again im getting a new issue- the solution no longer works.

Here is the error

Haven't tried Pd with PulseAudio, maybe something with internal sampling rates or buffer sizes? So maybe somebody can jump in here and help, but I would really recommend trying out JACK, particularly if you want to use anything else audio-related on your computer aside from Audacity (which can use ALSA directly but then you have the same hogging issues as before) as things like SuperCollider and Ardour also primarily use JACK as their means of talking with ALSA, and JACK tends be better at the low-latency, synchronous operation thing than PulseAudio, where latencies and synchronous operation don't mattery quite as much...

I have tried jack https://puredata.info/docs/JackRoutingMultichannelAndBrowserAudio/

Then i got this error
JACK: unable to connect to JACK server. Is JACK running?
JACK: server returned status 17

(This happens when i run pd as sudo).

But if i run it without sudo i get
JACKerror: Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
JACKerror: JackClient::AcquireSelfRealTime error

Both ways i cant use jack with pd. HOWEVER jack works fine with youtube!

@1mark I think you need to add your user to the audio group (adduser username audio) and your /etc/security/limits.d/audio.conf should look something like this:

@audio   -  rtprio     99
@audio   -  memlock    unlimited
#@audio   -  nice      -19

I've commented out the nice property, i think it defines priority, but you can go ahead and uncomment it if you want... You shouldn't have to run pd as sudo... also sometimes JACK crashes and has processes still running so it also helps to kill processes off if that happens

@dxk said:

So I've done what you said and the exact same errors happen with PD. Jack works fine, my microphone works, I can use skype etc. But I don't know why PD gives me these errors
Then i got this error
JACK: unable to connect to JACK server. Is JACK running?
JACK: server returned status 17

(This happens when i run pd as sudo).

But if i run it without sudo i get
JACKerror: Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
JACKerror: JackClient::AcquireSelfRealTime error

@1mark

Ok so finally fixed it @dxk well I followed what you said and I don't know if it done anything.
But I believe it was these that fixed the issue I did 1) then 2)
1)http://jackaudio.org/faq/linux_rt_config.html

2)Then the error didnt go away so I did
I select the interface -> hw:Codec (my Audio device) , save and start Jack Audio with success!