[pulseaudio-discuss] Moving sources and sinks

[Nick Thompson]

Hi Colin,

On May 3, 2008, at 5:53 AM, Colin Guthrie wrote:

> From what I can tell you've posted a couple questions but answered  
> them
> yourself within a day! It's not really fair of you to answer your
> questions yourself so quickly without giving anyone a chance to try  
> and
> be helpful :p

Lol.  I take your point.  I don't want to waste time so if I have an  
answer then I should let people know in case they are spending time  
typing up a response, and forgive me if the email was a little terse,  
I was becoming quite frustrated at the slowness of my progress.  I  
fully accept that my use of pulse might be somewhat unorthodox since  
it is in a speciailsed embedded system, however I also think that  
multiple device support and routing is of great interest, especially  
to the music community.  One of the issues of audio support on  
mainstream OS's like Max OS X is the lack of simultaneous synchronized  
multiple device support and this is an area where pulse has a great  
deal of potential.  Since the archives are online one would hope that  
my answers are of some use to others new to this sport.  And I will  
try to continue to share what I learn in the hope that it is of use to  
others who are following in the same track.

Phew.  Anyway the second question was not really answered fully.  It  
might be my imprecision in stating the problem so let me try to  
distill it to the bare bones:  For pulseaudio I'd like to know how or  
if a virtual stream can be created in pulse allowing on the fly  
redirection to an ALSA sink, that is the crux of the question that I'm  
searching for an answer.  I'd like in an alsa program (or set of  
programs) to write to a virtual device and have pulse route all audio  
on that device to a sink, and be able to switch sinks on the fly.   
I've spent a couple weeks looking into this and I think I've made  
quite a lot of progress but that part is not clear.

I could write a pulse module that will implement routing policy for  
individual stream, but since streams are created often I'd need to to  
track them (not too hard) and know when they are created (harder) and  
set the routing before the stream starts (no sure how to do this).  It  
seems there might be an easier way, but I don't know what that is.

So if you, or someone else, can fill be in on this it would be greatly  
appreciated.

Thanks!

Nick