[alsa-devel] Selecting correct input device port.

[dE]

On 10/29/14 13:06, Takashi Iwai wrote:
> At Tue, 28 Oct 2014 09:57:18 +0530,
> dE wrote:
>>
>> As I learn't in this mailng list, a device can typically handle only one
>> stream at a time unless it supports hardware mixing which's exposed via
>> subdevices in ALSA
>>
>> What does subdevice mean for input device?
>
> When a device can do multiplexing, the driver can give multiple
> substreams (= subdevices).
>
>> Do they mark physical ports
>> for input? If not how do I record from a specific input port?
>
> You can pass the subdevice number explicity.  It's -1 as default,
> which means to select the next free one.
>
>> Is it
>> automatically selected by the card?
>>
>> And what's 'input source' in ALSA mixer?
>
> It's usually a MUX to select the input source, e.g. line in or mic.
>
>
> Takashi
>

Input source for single subdevice right? I've 3 sub device, does it have 
to do anything with the fact that I've 3 input source in alsamixer? Do 
the 3 input source mark 3 different subdevices?

By muxing you mean muxing via software the multiple individual (and 
simultaneous) audio input streams as supported by the cards?