[pulseaudio-discuss] USB microphone works, monitoring doesn't

[Lennart Poettering]

On Mon, 10.08.09 16:09, Joe daLuz (jdaluz at gmail.com) wrote:

> Sorry if I was unclear. Let me try again.
> 
> The USB microphone captures audio as indicated by the successful recording
> and volume meter display. But I cannot hear what is being captured in my
> headphones *during* recording. (The same is true if I use speakers instead
> of headphones, though I wouldn't normally do that due to feedback).I can
> hear the captured audio when I play it back afterward.
> 
> I did not have this problem in the past with a microphone connected to mic
> in on the same sound card that the speakers/headphones are connected to. So
> I suspect there is something more complex I need to do to get a USB
> microphone appearing as a separate "sound card" to work the same way.
> 
> I provided "list_cards" output because I wasn't sure what information was
> needed to diagnose this. Please let me know if there is anything else you
> need.

Ah, so you want the USB audio input to be sent directly to your PCI
sound card's output?

Hmm, this is not supported. It's a much requested feature that we
allow direct connections between sources and sinks
(http://pulseaudio.org/ticket/90).

However, so far nobody worked on that. THis is much more complex than
it might seem sicne your sound card's clocks might deviate. It's
doable but not trivial. Code that handles clock deviations has already
been implemented in module-combine, so this could be used as a blueprint.

Patches welcome!

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4