[PD] Pd and pulseaudio (was: ALSA output error (restart failed): Broken pipe)

[Roman Haefeli]

On Don, 2013-01-31 at 13:12 -0500, Hans-Christoph Steiner wrote:
> Does it happen with Pd-vanilla 0.43.4 or 0.44?  I just take that code directly
> from Miller since I've never done anything with programming audio interfaces.
>  Pd definitely does not place nice with pulseaudio,

Pd 0.44 _does_ play nice with pulseaudio (input and output) when using
portaudio as backend and "pulse" as devcice. 
One can also launch Pd with the option '-pa'.
N.B.: '-pa' stands for portaudio which is not to be confused with
pulseaudio.

>  so make sure its not
> running when using Pd.  I use this to temporarily suspend pulse:
> 
> pasuspender pd-extended
> 
> Many people who use Pd a lot uninstall pulseaudio entirely.

Ok, let's clear some dust here. There seems a strong notion that
pulseaudio is interfering a lot with other audio applications and is
causing lots of troubles. Let me point out a few facts from a standard
Ubuntu 12.04 installation:

* When no pulseaudio client is playing, the sound device is not occupied
and thus non-compliant applications like Pd are _not_ blocked from
accessing the device. This is even the case when you pause a Youtube
movie in the browser. 

* pasuspender is actually not necessary in most cases. Only when some
pulseaudio client is actually playing, you may want to use pasuspender.
However, using pasuspender does not harm, even if it is not necessary

* Use "pasuspender -- pd-extended" instead of "pasuspender pd-extended",
so that options passed to pd-extended are bypassed by pasuspender.

* Uninstalling pulseaudio is completely unnecessary, as it doesn't solve
any problem. OTOH, it also doesn't harm. However, when pulseaudio is
installed and Firefox is playing some Youtube movie, you still are able
to grant Pd access to the sound device by using pasuspender. With no
pulseaudio installed, the flash-plugin might use ALSA directly and there
is no other way to stop it from blocking the sound device than to stop
firefox. If you don't know which application is currently using the
device, good luck with hunting. 
My point is: With pulseaudio it is actually easier to guarantee Pd
access to the sound device.

* Jackd (qjackctl, respectively) behaves similar to Pd: When no pulse
client is playing, you can just start it without any troubles.

  
Roman