Re: How to get access to all 16 channel controls on a multi-channel sound card

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Apr 27 2016 00:50, Caleb Crome wrote:
>>> Furtheremore, 'alsamixer' has a limitation of displayed channels up to 8.
>>> For example, see these lines:
>>> http://git.alsa-project.org/?p=alsa-utils.git;a=blob;f=alsamixer/mixer_display.c;h=b1f79d06522157c80d438b8429648ebe5bb269f0;hb=96db90e98a6040f680f4ebca1880268a2e1ab6cc#l587
>>>
>>
>> Is there any way to get a hold of and adjust the channels from user
>> space, without patches?  If we set aside alsamixer, is there an API
>> for adjusting those controls above channel 7?
>>
>>  Or perhaps I can call the controls by some other type in the USB descriptors?
>>
> 
> Ah, I think I found the answer to my own question: It appears I can use:
> 
> amixer cset numid=7 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 # for playback
> 
> and
> 
> amixer cset numid=3 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16   # for capture
> 
> to set the playback & record channels independently.

In this case, amixer uses 'high level control interface' of alsa
userspace library. In this case, an abstruction of 'simple mixer
interface' is dropped.

In a design of alsa userspace library, stuffs to handle control elements
are accumulated in several layers:

(near userspace applications)
 - smixer interface (an abstruction for something I don't know)
   - smixer backend modules (simple, etc...)
 - hctl interface (high level)
 - ctl interface (raw level)
   - ctl backend modules (hw, shm, etc...)
(near userspace/kernel interfaces)

When most applications use the smixer interface, it's better to fix it
for this purpose, I think.

For alsamixer, as Clemens addressed, we need to fix codes of alsamixer
itself. No other ways.

On Apr 27 2016 00:19, Caleb Crome wrote:
> BTW, is this available for purchase?

Yes. They're in consumer market as 'recording equipment'.


Regards

Takashi Sakamoto

------------------------------------------------------------------------------
Find and fix application performance issues faster with Applications Manager
Applications Manager provides deep performance insights into multiple tiers of
your business applications. It resolves application problems quickly and
reduces your MTTR. Get your free trial!
https://ad.doubleclick.net/ddm/clk/302982198;130105516;z
_______________________________________________
Alsa-user mailing list
Alsa-user@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/alsa-user



[Index of Archives]     [ALSA Devel]     [Linux Audio Users]     [Fedora Users]     [Fedora Desktop]     [Fedora SELinux]     [Big List of Linux Books]     [Yosemite News]     [Yosemite Photos]     [KDE Users]     [Fedora Tools]

  Powered by Linux