mirror of
https://github.com/mpv-player/mpv
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e24087509a
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@10990 b3059339-0415-0410-9bf9-f77b7e298cf2
292 lines
9.4 KiB
C
292 lines
9.4 KiB
C
/*
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** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
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** Copyright (C) 2003 M. Bakker, Ahead Software AG, http://www.nero.com
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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**
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** Any non-GPL usage of this software or parts of this software is strictly
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** forbidden.
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**
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** Commercial non-GPL licensing of this software is possible.
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** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
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**
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** $Id: mdct.c,v 1.28 2003/09/30 12:43:05 menno Exp $
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**/
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/*
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* Fast (I)MDCT Implementation using (I)FFT ((Inverse) Fast Fourier Transform)
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* and consists of three steps: pre-(I)FFT complex multiplication, complex
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* (I)FFT, post-(I)FFT complex multiplication,
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*
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* As described in:
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* P. Duhamel, Y. Mahieux, and J.P. Petit, "A Fast Algorithm for the
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* Implementation of Filter Banks Based on 'Time Domain Aliasing
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* Cancellation’," IEEE Proc. on ICASSP‘91, 1991, pp. 2209-2212.
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*
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*
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* As of April 6th 2002 completely rewritten.
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* This (I)MDCT can now be used for any data size n, where n is divisible by 8.
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*
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*/
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#include "common.h"
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#include "structs.h"
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#include <stdlib.h>
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#ifdef _WIN32_WCE
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#define assert(x)
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#else
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#include <assert.h>
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#endif
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#include "cfft.h"
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#include "mdct.h"
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/* const_tab[]:
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0: sqrt(2 / N)
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1: cos(2 * PI / N)
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2: sin(2 * PI / N)
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3: cos(2 * PI * (1/8) / N)
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4: sin(2 * PI * (1/8) / N)
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*/
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#ifndef FIXED_POINT
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#ifdef _MSC_VER
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#pragma warning(disable:4305)
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#pragma warning(disable:4244)
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#endif
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real_t const_tab[][5] =
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{
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{ COEF_CONST(0.0312500000), COEF_CONST(0.9999952938), COEF_CONST(0.0030679568),
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COEF_CONST(0.9999999265), COEF_CONST(0.0003834952) }, /* 2048 */
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{ COEF_CONST(0.0322748612), COEF_CONST(0.9999946356), COEF_CONST(0.0032724866),
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COEF_CONST(0.9999999404), COEF_CONST(0.0004090615) }, /* 1920 */
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{ COEF_CONST(0.0441941738), COEF_CONST(0.9999811649), COEF_CONST(0.0061358847),
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COEF_CONST(0.9999997020), COEF_CONST(0.0007669903) }, /* 1024 */
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{ COEF_CONST(0.0456435465), COEF_CONST(0.9999786019), COEF_CONST(0.0065449383),
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COEF_CONST(0.9999996424), COEF_CONST(0.0008181230) }, /* 960 */
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{ COEF_CONST(0.0883883476), COEF_CONST(0.9996988177), COEF_CONST(0.0245412290),
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COEF_CONST(0.9999952912), COEF_CONST(0.0030679568) }, /* 256 */
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{ COEF_CONST(0.0912870929), COEF_CONST(0.9996573329), COEF_CONST(0.0261769500),
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COEF_CONST(0.9999946356), COEF_CONST(0.0032724866) } /* 240 */
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#ifdef SSR_DEC
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,{ COEF_CONST(0.062500000), COEF_CONST(0.999924702), COEF_CONST(0.012271538),
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COEF_CONST(0.999998823), COEF_CONST(0.00153398) }, /* 512 */
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{ COEF_CONST(0.176776695), COEF_CONST(0.995184727), COEF_CONST(0.09801714),
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COEF_CONST(0.999924702), COEF_CONST(0.012271538) } /* 64 */
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#endif
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};
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#else
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real_t const_tab[][5] =
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{
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{ COEF_CONST(1), COEF_CONST(0.9999952938), COEF_CONST(0.0030679568),
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COEF_CONST(0.9999999265), COEF_CONST(0.0003834952) }, /* 2048 */
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{ COEF_CONST(/* sqrt(1024/960) */ 1.03279556), COEF_CONST(0.9999946356), COEF_CONST(0.0032724866),
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COEF_CONST(0), COEF_CONST(0.0004090615) }, /* 1920 */
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{ COEF_CONST(1), COEF_CONST(0.9999811649), COEF_CONST(0.0061358847),
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COEF_CONST(0.9999997020), COEF_CONST(0.0007669903) }, /* 1024 */
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{ COEF_CONST(/* sqrt(512/480) */ 1.03279556), COEF_CONST(0.9999786019), COEF_CONST(0.0065449383),
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COEF_CONST(0.9999996424), COEF_CONST(0.0008181230) }, /* 960 */
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{ COEF_CONST(1), COEF_CONST(0.9996988177), COEF_CONST(0.0245412290),
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COEF_CONST(0.9999952912), COEF_CONST(0.0030679568) }, /* 256 */
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{ COEF_CONST(/* sqrt(256/240) */ 1.03279556), COEF_CONST(0.9996573329), COEF_CONST(0.0261769500),
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COEF_CONST(0.9999946356), COEF_CONST(0.0032724866) } /* 240 */
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#ifdef SSR_DEC
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,{ COEF_CONST(0), COEF_CONST(0.999924702), COEF_CONST(0.012271538),
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COEF_CONST(0.999998823), COEF_CONST(0.00153398) }, /* 512 */
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{ COEF_CONST(0), COEF_CONST(0.995184727), COEF_CONST(0.09801714),
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COEF_CONST(0.999924702), COEF_CONST(0.012271538) } /* 64 */
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#endif
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};
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#endif
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uint8_t map_N_to_idx(uint16_t N)
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{
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/* gives an index into const_tab above */
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/* for normal AAC deocding (eg. no scalable profile) only */
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/* index 0 and 4 will be used */
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switch(N)
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{
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case 2048: return 0;
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case 1920: return 1;
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case 1024: return 2;
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case 960: return 3;
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case 256: return 4;
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case 240: return 5;
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#ifdef SSR_DEC
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case 512: return 6;
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case 64: return 7;
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#endif
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}
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return 0;
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}
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mdct_info *faad_mdct_init(uint16_t N)
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{
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uint16_t k, N_idx;
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real_t cangle, sangle, c, s, cold;
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real_t scale;
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mdct_info *mdct = (mdct_info*)malloc(sizeof(mdct_info));
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assert(N % 8 == 0);
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mdct->N = N;
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mdct->sincos = (complex_t*)malloc(N/4*sizeof(complex_t));
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mdct->Z1 = (complex_t*)malloc(N/4*sizeof(complex_t));
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N_idx = map_N_to_idx(N);
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scale = const_tab[N_idx][0];
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cangle = const_tab[N_idx][1];
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sangle = const_tab[N_idx][2];
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c = const_tab[N_idx][3];
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s = const_tab[N_idx][4];
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/* (co)sine table build using recurrence relations */
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/* this can also be done using static table lookup or */
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/* some form of interpolation */
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for (k = 0; k < N/4; k++)
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{
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#if 1
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RE(mdct->sincos[k]) = -1*MUL_C_C(c,scale);
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IM(mdct->sincos[k]) = -1*MUL_C_C(s,scale);
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cold = c;
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c = MUL_C_C(c,cangle) - MUL_C_C(s,sangle);
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s = MUL_C_C(s,cangle) + MUL_C_C(cold,sangle);
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#else
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/* no recurrence, just sines */
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RE(mdct->sincos[k]) = -scale*cos(2.0*M_PI*(k+1./8.) / (float)N);
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IM(mdct->sincos[k]) = -scale*sin(2.0*M_PI*(k+1./8.) / (float)N);
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#endif
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}
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/* initialise fft */
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mdct->cfft = cffti(N/4);
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return mdct;
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}
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void faad_mdct_end(mdct_info *mdct)
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{
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if (mdct != NULL)
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{
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cfftu(mdct->cfft);
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if (mdct->Z1) free(mdct->Z1);
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if (mdct->sincos) free(mdct->sincos);
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free(mdct);
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}
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}
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void faad_imdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
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{
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uint16_t k;
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complex_t x;
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complex_t *Z1 = mdct->Z1;
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complex_t *sincos = mdct->sincos;
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uint16_t N = mdct->N;
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uint16_t N2 = N >> 1;
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uint16_t N4 = N >> 2;
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uint16_t N8 = N >> 3;
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/* pre-IFFT complex multiplication */
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for (k = 0; k < N4; k++)
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{
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RE(Z1[k]) = MUL_R_C(X_in[N2 - 1 - 2*k], RE(sincos[k])) - MUL_R_C(X_in[2*k], IM(sincos[k]));
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IM(Z1[k]) = MUL_R_C(X_in[2*k], RE(sincos[k])) + MUL_R_C(X_in[N2 - 1 - 2*k], IM(sincos[k]));
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}
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/* complex IFFT, any non-scaling FFT can be used here */
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cfftb(mdct->cfft, Z1);
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/* post-IFFT complex multiplication */
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for (k = 0; k < N4; k++)
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{
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RE(x) = RE(Z1[k]);
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IM(x) = IM(Z1[k]);
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RE(Z1[k]) = MUL_R_C(RE(x), RE(sincos[k])) - MUL_R_C(IM(x), IM(sincos[k]));
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IM(Z1[k]) = MUL_R_C(IM(x), RE(sincos[k])) + MUL_R_C(RE(x), IM(sincos[k]));
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}
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/* reordering */
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for (k = 0; k < N8; k++)
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{
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X_out[ 2*k] = IM(Z1[N8 + k]);
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X_out[ 1 + 2*k] = -RE(Z1[N8 - 1 - k]);
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X_out[N4 + 2*k] = RE(Z1[ k]);
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X_out[N4 + 1 + 2*k] = -IM(Z1[N4 - 1 - k]);
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X_out[N2 + 2*k] = RE(Z1[N8 + k]);
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X_out[N2 + 1 + 2*k] = -IM(Z1[N8 - 1 - k]);
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X_out[N2 + N4 + 2*k] = -IM(Z1[ k]);
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X_out[N2 + N4 + 1 + 2*k] = RE(Z1[N4 - 1 - k]);
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}
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}
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#ifdef LTP_DEC
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void faad_mdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
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{
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uint16_t k;
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complex_t x;
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complex_t *Z1 = mdct->Z1;
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complex_t *sincos = mdct->sincos;
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uint16_t N = mdct->N;
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uint16_t N2 = N >> 1;
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uint16_t N4 = N >> 2;
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uint16_t N8 = N >> 3;
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real_t scale = REAL_CONST(N);
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/* pre-FFT complex multiplication */
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for (k = 0; k < N8; k++)
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{
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uint16_t n = k << 1;
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RE(x) = X_in[N - N4 - 1 - n] + X_in[N - N4 + n];
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IM(x) = X_in[ N4 + n] - X_in[ N4 - 1 - n];
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RE(Z1[k]) = -MUL_R_C(RE(x), RE(sincos[k])) - MUL_R_C(IM(x), IM(sincos[k]));
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IM(Z1[k]) = -MUL_R_C(IM(x), RE(sincos[k])) + MUL_R_C(RE(x), IM(sincos[k]));
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RE(x) = X_in[N2 - 1 - n] - X_in[ n];
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IM(x) = X_in[N2 + n] + X_in[N - 1 - n];
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RE(Z1[k + N8]) = -MUL_R_C(RE(x), RE(sincos[k + N8])) - MUL_R_C(IM(x), IM(sincos[k + N8]));
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IM(Z1[k + N8]) = -MUL_R_C(IM(x), RE(sincos[k + N8])) + MUL_R_C(RE(x), IM(sincos[k + N8]));
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}
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/* complex FFT, any non-scaling FFT can be used here */
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cfftf(mdct->cfft, Z1);
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/* post-FFT complex multiplication */
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for (k = 0; k < N4; k++)
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{
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uint16_t n = k << 1;
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RE(x) = MUL(MUL_R_C(RE(Z1[k]), RE(sincos[k])) + MUL_R_C(IM(Z1[k]), IM(sincos[k])), scale);
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IM(x) = MUL(MUL_R_C(IM(Z1[k]), RE(sincos[k])) - MUL_R_C(RE(Z1[k]), IM(sincos[k])), scale);
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X_out[ n] = RE(x);
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X_out[N2 - 1 - n] = -IM(x);
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X_out[N2 + n] = IM(x);
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X_out[N - 1 - n] = -RE(x);
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}
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}
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#endif
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