mdct.c

the mpeg2/4 aac decoder

/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
**  
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
** 
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
** 
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software 
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through [e-mail].
**
** $Id: mdct.c,v 1.43 2004/09/04 14:56:28 menno Exp $
**/

/*
 * Fast (I)MDCT Implementation using (I)FFT ((Inverse) Fast Fourier Transform)
 * and consists of three steps: pre-(I)FFT complex multiplication, complex
 * (I)FFT, post-(I)FFT complex multiplication,
 * 
 * As described in:
 *  P. Duhamel, Y. Mahieux, and J.P. Petit, "A Fast Algorithm for the
 *  Implementation of Filter Banks Based on 'Time Domain Aliasing
 *  Cancellation