Hallo, Joseph Barrows hat gesagt: // Joseph Barrows wrote:
this is not strictly PD; can someone inform me how sound works in linux ? i am very confused about alsa, jack, pulse, oss, <hardware device name>,
OSS is a name of the old soundcard drivers in the Linux kernel. With these, soundcards were accessed by opening files like /dev/dsp0 and writing samples to it. ALSA replaced OSS in kernels several years ago, it uses a different way to let applications speak to the soundcard, but it provides the old device files like /dev/dsp0 for backwards-compatibility, so that old apps still work. ALSA uses abstract, virtual device names like "hw:0" or "plughw:0" or "default" or "mynicesoundcard" (yes, you can define your own names!). These names are defined either internally or in a configuration file like /etc/asound.conf or ~/.asoundrc
Pd was started when only OSS was available, so it has OSS decvice support which is used over ALSA's OSS-emulation when you choose "OSS" as audio system in Pd and have an ALSA kernel (you have one!), or use ALSA directly by choosing ALSA in Pd. Pd over ALSA will try to use either hw:X or plughw:X (with X being a number starting at 0 for your first card).
Now the next layer is Jack. As both ALSA and OSS don't provide a (simple) way to connect applications together (they only deal with soundcards) Paul Davis and others developed Jack. It usually uses the ALSA system to access soundcards (but could use OSS as well) and with a tool like "qjackctl" you can connect e.g. Pd to Ardour, when both are running over jack. "jackd" is the Jack Server Daemon that has to be running for this to work. As soon as jackd is running, it completely takes over the soundcard, so non-jack apps cannot produce sound anymore.
There are other sound servers similar to jack, but they aren't targetting professtional audio production, so you generally won't see them very often in the Pd world. PulseAudio is such a soundserver. Make sure you only start one! Check with a process listing tool like "ps aux"
I dont use audio a lot, but would love audio to work on my machine. today PD cant connect to any audio (in or out) yesterday the mic input was stuck feeding through the speakers (without PD) but PD could get input (with a lot of noise).
"Not enough data. System shut down ..."
If you can provide more info we might be able to help with that proble,. Any error messages?
I want it to 'just work' ie all apps can access the inputs and all apps can access the outputs (mixed).
I'd recommend to use Jackd and only run Jack-aware applications.
ideally there would also be the option of a PD like patching environment to re-patch a programs output to become another programs input (EG cd-audio out --> pd-audio in (fun patch)--> hardware line out
Somehow gstreamer tries to be this, it also supports jackd as backend. But usually when doing music most Pd users I know don't want to be surprised by "You have new mail!" sounds at full volume.
Ciao
Frank Barknecht