devices/subdevices, hw:/plughw:

[Florian Bomers <Florian.Bomers@sun.com>]

(I initially posted this to alsa-user without answers. Hope to get more lucky
here...)

Hi,

sorry for those general questions, but I wasn't able to find anything on the
archives or in the ALSA documentation.

What is the meaning of devices vs. subdevices ? What is an example where a
device would have several subdevices, as opposed to the card having several
devices ? I want to display a list of available "ports" where the user can send
the audio generated by the program. If a device has several subdevices, would I
include them in the list, or just list the devices for each card ?

My program successfully lists the cards with their devices and subdevices for
hw: (i.e. snd_ctl_open("hw:0") ). However, this does not work for the plughw:
way, although from what I understood, I want to use plughw: (as it is supposed 
to support automatic sample rate conversion). How do I iterate all available 
plughw: "cards", devices, and subdevices? Or can I assume that if hw:0,0 exists, 
that plughw:0,0 is the same card/device - and I just can't iterate available 
plughw:'s directly ?

Thanks!
Florian


-- 
Florian Bomers
Java Sound
Java Software/Sun Microsystems, Inc.
http://java.sun.com/products/java-media/sound/


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