pkmital / pkmFFT

pkmFFT provide simple interfaces to the Accelerate.framework for performing vectorized FFT. pkmSTFT builds on pkmFFT to perform Short Time Fourier Transform efficiently using vectorized ops. Also handles options for windowing. pkmDCT provides a simple discrete cosine transform using Accelerate and pkmMatrix.

 *  Real FFT wraper for Apple's Accelerate Framework
 *  and STFT implementation making use of Apple's Accelerate Framework (pkmFFT)
 *
 *  Created by Parag K. Mital - http://pkmital.com 
 *  Contact: [e-mail]
 *
 *  Copyright 2011 Parag K. Mital. All rights reserved.
 * 
 *	Permission is hereby granted, free of charge, to any person
 *	obtaining a copy of this software and associated documentation
 *	files (the "Software"), to deal in the Software without
 *	restriction, including without limitation the rights to use,
 *	copy, modify, merge, publish, distribute, sublicense, and/or sell
 *	copies of the Software, and to permit persons to whom the
 *	Software is furnished to do so, subject to the following
 *	conditions:
 *	
 *	The above copyright notice and this permission notice shall be
 *	included in all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,	
 *	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *	OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *	HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *	WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *	OTHER DEALINGS IN THE SOFTWARE.
 *
 *  Additional resources: 
 *      http://developer.apple.com/library/ios/#documentation/Accelerate/Reference/vDSPRef/Reference/reference.html
 *      http://developer.apple.com/library/ios/#documentation/Performance/Conceptual/vDSP_Programming_Guide/SampleCode/SampleCode.html
 *      http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework
 *      http://stackoverflow.com/questions/1964955/audio-file-fft-in-an-os-x-environment
 *     
 *
 *  This code is a very simple interface for Accelerate's fft/ifft code.
 *  It was built out of hacking Maximilian (Mick Grierson and Chris Kiefer) and
 *  the above mentioned resources for performing a windowed FFT which could
 *  be used underneath of an STFT implementation
 *
 *  FFT Usage:
 *
 *  // be sure to either use malloc or __attribute__ ((aligned (16))
 *  float *sample_data = (float *) malloc (sizeof(float) * 4096);
 *  float *allocated_magnitude_buffer =  (float *) malloc (sizeof(float) * 2048);
 *  float *allocated_phase_buffer =  (float *) malloc (sizeof(float) * 2048);
 *
 *  pkmFFT *fft;
 *  fft = new pkmFFT(4096);
 *  fft.forward(0, sample_data, allocated_magnitude_buffer, allocated_phase_buffer);
 *  fft.inverse(0, sample_data, allocated_magnitude_buffer, allocated_phase_buffer);
 *  delete fft;
 *
 *
 *  STFT Usage:
 *  // be sure to either use malloc or __attribute__ ((aligned (16))
 *  size_t buffer_size = 4096;
 *  float *sample_data = (float *) malloc (sizeof(float) * buffer_size);
 *  pkm::Mat magnitude_matrix, phase_matrix;
 *
 *  pkmSTFT *stft;
 *  stft = new pkmSTFT(512);
 *  stft.STFT(sample_data, buffer_size, magnitude_matrix, phase_matrix);
 *  fft.ISTFT(sample_data, buffer_size, magnitude_matrix, phase_matrix);
 *  delete stft;