Re: Basic question
Re: Basic question
- Subject: Re: Basic question
- From: Laurent Cerveau <email@hidden>
- Date: Wed, 27 Mar 2002 12:02:19 +0100
On Wednesday, March 27, 2002, at 11:35 AM, Matthew Johnson wrote:
Very simple question I suspect but I can't find the answer anywhere.
Following is my IOProc for recording from my microphone. It works well.
The
only thing I am wondering is what is the actual data in the array of
floats?
What is its scale?. How do I retrieve the Amplitude and frequency from
the
data?
What are you trying to achieve?
The data will be ... the microphone input data converted from native
device format (16 bits, 8bits...) to floats . You can ask for the
properties of the device through CoreAudio calls
(AudioDeviceGetPropertyInfo, AudioDeviceGetProperty), or for the stream
info, but this will give you the settings of the hardware device not
about the data themselves.
If you want to do further analysis of the data you will have to deal
yourself with FFTs and other DSP niceties (in this case you may want to
have a look at the vecLib framework)
Laurent
Laurent Cerveau
Applications Division
Apple Computer Inc.
email@hiddenrent
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