Re: quicktime waveform
Re: quicktime waveform
- Subject: Re: quicktime waveform
- From: Darrin Cardani <email@hidden>
- Date: Fri, 9 Jan 2004 09:40:04 -0600
At 10:00 PM -0800 1/8/04, Jacob Chapa <email@hidden> wrote:
anyone know of any open-source app that shows how to create those bars
when music plays?
Which are you looking for, the waveform, or the frequency breakdown?
Do you want what your stereo's equalizer displays or what an
oscilloscope would display? The waveform (what an oscilloscope would
display), you need to tell QuickTime what format you want the samples
in by calling MovieExportSetSampleDescription (), then you need to
tell it to do the export by calling MovieExportToHandle () or a
related function.
To get the frequency breakdown (like your equalizer would display),
you need to do the above, then run a Fast Fourier Transform on it
(aka FFT). Apple has various packages that will perform the FFT, such
as the vDSP package.
For more info on this, you'll probably want to ask on the QuickTime
developer list. You can sign up at <
http://public.lists.apple.com/>.
Darrin
--
Darrin Cardani - email@hidden
President, Buena Software, Inc.
<
http://www.buena.com/>
Video, Image and Audio Processing Development
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