Re: multi-channel audio output in QT6.1
Re: multi-channel audio output in QT6.1
- Subject: Re: multi-channel audio output in QT6.1
- From: Mark Coniglio <email@hidden>
- Date: Mon, 13 Jan 2003 08:59:19 -0500
(I'm posting this both to QT list and CoreAudio -- I thought it would
be interesting in both places.)
Regarding multi-channel output... I just finished up writing a Sound
Manager Sound Component that allows me to do multi-channel audio
output OS 9 and OS X.
In OS 9, I wrote a little ASIO class that feeds data to the hardware
device. In OS X, I created a similar class using HAL.
Then, I wrote a sound component that I register when my program
starts up. All it really does is provide a destination for the sound
in the sound manager. The main app communicates with the component
via a callback mechanism. I register the component 4 times: once for
channels 1-2, once for channels 3-4, etc.
When sound is playing through the component, the main app (via the
classes mentioned above) receives a request for audio from the
hardware. It sends a message to the component asking for the sound
data. The sound component returns that data, and the ASIO/HAL class
feeds it off to the hardware interface, doing whatever conversions
are necessary. (HAL always wants float32s, while the SM seems to only
generates SInt16s)
Having done this, it now becomes possible to route the sound from
different QuickTime movies to multiple outputs on my MOTU 828.
Works like a charm setup, though I haven't yet done extensive testing
due to my lack of a variety of hardware to test it on. My beta
testers will be doing that soon.
Anyway, it's a possible, not too difficult, and cross-OS solution to
the problem.
Ciao,
Mark
--
================================================================
Mark Coniglio, Artistic Co-Director | email@hidden
Troika Ranch Dance Theater |
http://www.troikaranch.org
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