On Thu, 2010-03-04 at 12:31 +0000, Marko Vojinovic wrote: > On Thursday 04 March 2010 04:32:35 am Rick Sewill wrote: > > I believe many software programs use alsa. > > I believe alsa, in turn, uses pulseaudio. > > No. Userland apps talk to pulseaudio, which talks to alsa which talks to > hardware. That is a natural flow of audio data (when doing playback). > Pulseaudio is built and works on top of alsa. > > > I must add a caveat. I believe programs can be configured to use alsa. > > If a program is configured to use alsa, the alsa-pulseaudio plugin would catch > it trying to talk to alsa and redirect the communication to pulseaudio, which > would mimic alsa for that app. After pulseaudio does its processing, it > forwards the results to alsa. Only pulseaudio actually talks to the real alsa. > > Of course, you can disable the plugin or pulseaudio and let apps talk directly > to alsa, but that would be a broken configuration. > > > I believe some programs can be configured to use pulseaudio, bypassing > > alsa. I believe some programs can be configured to bypass pulseaudio, > > and go straight to the hardware device drivers. > > All programs should be configured to use pulseaudio, if they support it. If > not, they should be configured to use alsa, whereby the alsa-pulseaudio-plugin > will interfere as above. Hardware device drivers are part of alsa, and no user > app should ever talk to hardware directly. > > > pavucontrol > > Also, there are two mixers in the story --- the hardware mixer (for alsa) and > the userland mixer (pavucontrol, for pulseaudio). In regular circumstances you > never want to mess with the hardware mixer, since it is used by pulseaudio > when communicating to alsa. The hardware mixer is not easy to access either, > you must specifically ask for it to be displayed, using appropriate switches > in, say, "alsamixer" app. > > The only mixer that a user should actually use is pavucontrol. Or kmix or > gnome volume control mixer or some other similar thing. They all handle > basically the same controls (using different GUIs) and use pulseaudio in the > background. > > I hope this clears things up a little. > > HTH, :-) > Marko > > Thank you for your explanation! I admit my ignorance. So it's backwards from what I thought. Pulseaudio goes to alsa to the hardware? -Rick -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
