[linux-audio-user] Re: asoundrc and aplay

From: Arnold Krille <arnold.krille@email-addr-hidden>
Date: Mon Feb 20 2006 - 14:48:50 EET

While most of your questions are already answered...

2006/2/17, conrad berhörster <conrad.berhoerster@email-addr-hidden>:
> > Enough things have been said about way two soundcards without syncing
> > can't be used as one multichannel device, so I won't repeat it here.
> yes, i know. i have read them too. maybe you can explain, what you mean
> exactly with the notion "multichannel device". Is it just a couple of IOs,
> without sync, or are the requirements for pro audios (with sync).

Well "one multichannel-device" means one device as seen by the
software and exposed by the driver which can have any number of more
the two channels. Well, strictly it is more than one channel, so even
a stereo-device is already a multichannel device...
This is done in hardware by either on big'n'good AD/DA-unit which does
multiplexing of the IO's or by multiple AD/DA-units that are
sample-synced by a common clock. [1]

The problem as already explained a lot of times is to _really_ sync
several devices, which hw-manufactures solve in hardware on the
chip/board but is very hard / impossible to do in software.

> if all this stuff isn't possible, do you have any idea to fix the problem.

- learn the alsa-interface and use some jitter-buffers
- try to run several jackd (one for each hardware-device you want to
use) and connect your app with all of them (again you have to use
jitter-buffers)
- get a device with the desired number of inputs and outputs (easiest
but expensive solution)

Enough said, I should work now,

Arnold

[1] While I believe that most soundcards will use one fast ADC (for
input) and multiplex the incomming signals, I am working here with
some devices that reach a samplerat of 4GHz by multiplexing the one
input-signal to four 1Ghz ADC's. Quite the opposite but really works
:-)

--
visit http://dillenburg.dyndns.org/~arnold/
---
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Received on Sun Feb 26 20:16:44 2006

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