<html> <head> <style></style> </head> <body class='hmmessage'> Thanks Col! That addresses my query perfectly. By "mixer" I meant a DSP that "mixes and routes" multiple analog and digital inputs to analog (5.1) or digital output.   I am working on the implementation of a audio policy management module using PA. It requires me to understand both ;) the use of pulseaudio by apps and the implementation of PA/ ALSA mixer or sound card drivers on an automotive platform.   ~J <A href="mailto:jayan_john@hotmail.com">jayan_john@hotmail.com</A> "Woking on Meego, breaking in PulseAudio"   > To: pulseaudio-discuss@lists.freedesktop.org > From: gmane@colin.guthr.ie > Date: Tue, 14 Jun 2011 09:51:00 +0100 > Subject: Re: [pulseaudio-discuss] association of pa_stream to mixer input channel > > 'Twas brillig, and jayan john at 14/06/11 06:12 did gyre and gimble: > > 1. Does the pa_stream_connect_playback() call allocate an input channel > > on the mixer and connect it to the sink device? > > Not really what you are referring to as "the mixer" or an "allocated > input channel" here but this command does indeed connect a playback > stream. This will be needed if you want to playback any audio. After the > stream is connected it will be allocated to a sink according to various > routing decisions in PA itself. It may at some point be moved to a new > device at a later time (unless you pass the PA_STREAM_DONT_MOVE flag IIRC). > > > 2. Would it allocate 6 input channels on the mixer if I have a 5.1 > > channel map for my pa_stream? > > Again, I'm not really sure what "the mixer" refers to here. But your > stream will have as many channels as you say it has in it's channel map > like you say. You can ultimately connect a stereo stream to a 5.1 sink > and PA will upmix, and likewise you can connect a 6ch stream to a stereo > sink and it will downmix. > > Ultimately, as an app developer, you should just care about your stream > and not worry about the sinks :) > > Col > > > -- > > Colin Guthrie > gmane(at)colin.guthr.ie > http://colin.guthr.ie/ > > Day Job: > Tribalogic Limited [http://www.tribalogic.net/] > Open Source: > Mageia Contributor [http://www.mageia.org/] > PulseAudio Hacker [http://www.pulseaudio.org/] > Trac Hacker [http://trac.edgewall.org/] > > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss </body> </html>