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Re: Question Re. Interleaved Sound Input
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Re: Question Re. Interleaved Sound Input


  • Subject: Re: Question Re. Interleaved Sound Input
  • From: Jeff Moore <email@hidden>
  • Date: Wed, 26 Mar 2003 11:30:05 -0800

The ordering of the channels in a frame of interleaved linear PCM data is 1 2 3 ... N, where N is the number of channels in the stream.

One thing you should be aware of is that audio devices all present their stream layout in different ways. Some, like USB devices will have just one stream with all the channels interleaved. While others will have many streams each with a single mono channel. And still others will have some number of streams where each stream has a different number of channels in it.

To properly support all audio devices, you need to be sure you are ready to deal with any combination of streams and channels the audio device might have. The HAL provides properties, such as kAudioDevicePropertyStreamConfiguration, to help you figure out ahead of time how a device is laid out.

On Wednesday, March 26, 2003, at 10:43 AM, Bill Kapralos wrote:

Hello

I am new to Mac OS X sound development and in the process of creating some
software which requries the input of sound from four channels. I am
having some difficulties in getting this working properly so perhaps i
someone can let me know what the format for interleaved samples is when
using coreAudio. For example, after obtaining the buffer of data in the
IOProc is the format each 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4... where 1,2,3,4
refer to single samples (four bytes/floats) from channels 1 - 4
respectively?

Any help would be greatly appreciated!

Thanks!
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--

Jeff Moore
Core Audio
Apple
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References: 
 >Question Re. Interleaved Sound Input (From: Bill Kapralos <email@hidden>)

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