[pulseaudio-discuss] Using PA with multiple sound cards

Colin Guthrie gmane at colin.guthr.ie
Sat Mar 21 01:27:56 PDT 2009

'Twas brillig, and Mark Greenwood at 20/03/09 22:53 did gyre and gimble:
> On Friday 20 March 2009 21:08:57 Mark Greenwood wrote:
>> Can I make certain modules 'bind' to certain cards?
>> I've got an internal sound card and a USB sound card. The USB is
>> permanently connected. I'd like the internal sound card to be the
>> default but I'd like module-rtp-recv to 'bind' to the USB card. The
>> internal card is alsa card 0 and the USB card is alsa card 1.
>> Is this possible? How would I configure it?
>> Thanks,
> OK, replying to myself again. I found the sink= parameter for
> module-rtp-recv.
> Now can anybody explain why RTP only works when I leave pavucontrol
> open on the sending machine? As soon as I close it the audio goes all
> choppy or even disappears altogether.
> I'd try and use zeroconf-discovered sinks but I've still not found
> out (or had any explanation for) why that causes huge CPU usage.
> I reiterate that all this worked perfectly with 0.9.10. 0.9.14 and
> greater have been nothing but trouble. I'm currently using tsched=0
> if that makes any difference.
> Should I just log all these things as bugs and shut up?

I think it's quite good to get an understanding of the problems here,
but adding as bugs is wise too.

As you discovered the rtp stuff works by piggy backing onto another

So if you want to sent the contents of your USB card out over RTP to the
world, you would loaduk module-rtp-send and set the source= argument to
be that of the "monitor" stream of your USB sink.

I have no idea why pavucontrol running would cause things to stablise 
but closing it causes things to go awry :s

If you can perhaps provide a simple series of steps including 
pactl/pacmd commands to get the same setup as you then I or other users 
can test and confirm things?



Colin Guthrie

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