RE: question about Audio Converter: channel mapping without rate conversion?
RE: question about Audio Converter: channel mapping without rate conversion?
- Subject: RE: question about Audio Converter: channel mapping without rate conversion?
- From: "Patzer, Curtis" <email@hidden>
- Date: Wed, 30 Jul 2003 09:23:53 -0700
- Thread-topic: RE: question about Audio Converter: channel mapping without rate conversion?
I'm developing on OSX V10.2.6, using CW8.3
I'm updating the auditioning portion of a Mac audio tool which using
ASIO to also use Core Audio, so users can use multi-channel audio
hardware (i.e. 6 outputs) in OSX. It's a Carbon app, so I'm using
CFM->MachO patching to get at frameworks.
The cross-platform sound library I'm using lets me set an output
sampling rate, and the number of output channels (typically 2, 4 or 6).
I'm letting the user set these attributes to model other software which
uses the cross platform library. I'm also letting the user map each
library output to a particular hardware output. The user selects the
desired hardware by making it the Default Output.
I basically copied the DefaultOutputUnit - Using Audio Converter
example, replacing the sine generator code with calls to the sound
library to generate audio into the input buffer. I also set the Audio
Converter's kAudioConverterChannelMap property with an array containing
my channel map.
For testing, I've set the channel map to only pass one channel through
from the library to the hardware. With the library and the hardware
using different sample rates, the single channel sounds as expected, but
if I set the library and hardware sample rates to be the same (and the
number of library channels is the same as the number of hardware
channels - stereo), the Audio Converter ignores my mapping, and passes
all channels through.
curtis
-----Original Message-----
From: Doug Wyatt [
mailto:email@hidden]
Sent: Tuesday, July 29, 2003 12:16 PM
To: Patzer, Curtis
Cc: email@hidden
Subject: Re: question about Audio Converter: channel mapping without
rate conversion?
That should work. Can you be more explicit about what you're doing? Are
you on Jaguar or a Panther seed?
Doug
On Tuesday, July 29, 2003, at 9:42 AM, Patzer, Curtis wrote:
>
I'm using an Audio Converter to resample and to remap channels. It
>
works
>
as I expect, except when the input and output stream sample rates are
>
the same. Then my channel mapping is ignored. How can I remap without
>
resampling?
>
>
>
>
Curtis Patzer
>
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