mpv/libfaad2/mdct.c

301 lines
8.1 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*
** 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 Mpeg4AAClicense@nero.com.
**
** Initially modified for use with MPlayer by Arpad Gereöffy on 2003/08/30
** $Id: mdct.c,v 1.4 2004/06/23 13:50:51 diego Exp $
** detailed CVS changelog at http://www.mplayerhq.hu/cgi-bin/cvsweb.cgi/main/
**/
/*
* 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," IEEE Proc. on ICASSP91, 1991, pp. 2209-2212.
*
*
* As of April 6th 2002 completely rewritten.
* This (I)MDCT can now be used for any data size n, where n is divisible by 8.
*
*/
#include "common.h"
#include "structs.h"
#include <stdlib.h>
#ifdef _WIN32_WCE
#define assert(x)
#else
#include <assert.h>
#endif
#include "cfft.h"
#include "mdct.h"
#include "mdct_tab.h"
mdct_info *faad_mdct_init(uint16_t N)
{
mdct_info *mdct = (mdct_info*)faad_malloc(sizeof(mdct_info));
assert(N % 8 == 0);
mdct->N = N;
/* NOTE: For "small framelengths" in FIXED_POINT the coefficients need to be
* scaled by sqrt("(nearest power of 2) > N" / N) */
/* RE(mdct->sincos[k]) = scale*(real_t)(cos(2.0*M_PI*(k+1./8.) / (real_t)N));
* IM(mdct->sincos[k]) = scale*(real_t)(sin(2.0*M_PI*(k+1./8.) / (real_t)N)); */
/* scale is 1 for fixed point, sqrt(N) for floating point */
switch (N)
{
case 2048: mdct->sincos = (complex_t*)mdct_tab_2048; break;
case 256: mdct->sincos = (complex_t*)mdct_tab_256; break;
#ifdef LD_DEC
case 1024: mdct->sincos = (complex_t*)mdct_tab_1024; break;
#endif
#ifdef ALLOW_SMALL_FRAMELENGTH
case 1920: mdct->sincos = (complex_t*)mdct_tab_1920; break;
case 240: mdct->sincos = (complex_t*)mdct_tab_240; break;
#ifdef LD_DEC
case 960: mdct->sincos = (complex_t*)mdct_tab_960; break;
#endif
#endif
#ifdef SSR_DEC
case 512: mdct->sincos = (complex_t*)mdct_tab_512; break;
case 64: mdct->sincos = (complex_t*)mdct_tab_64; break;
#endif
}
/* initialise fft */
mdct->cfft = cffti(N/4);
#ifdef PROFILE
mdct->cycles = 0;
mdct->fft_cycles = 0;
#endif
return mdct;
}
void faad_mdct_end(mdct_info *mdct)
{
if (mdct != NULL)
{
#ifdef PROFILE
printf("MDCT[%.4d]: %I64d cycles\n", mdct->N, mdct->cycles);
printf("CFFT[%.4d]: %I64d cycles\n", mdct->N/4, mdct->fft_cycles);
#endif
cfftu(mdct->cfft);
faad_free(mdct);
}
}
void faad_imdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
{
uint16_t k;
complex_t x;
#ifdef ALLOW_SMALL_FRAMELENGTH
#ifdef FIXED_POINT
real_t scale, b_scale = 0;
#endif
#endif
ALIGN complex_t Z1[512];
complex_t *sincos = mdct->sincos;
uint16_t N = mdct->N;
uint16_t N2 = N >> 1;
uint16_t N4 = N >> 2;
uint16_t N8 = N >> 3;
#ifdef PROFILE
int64_t count1, count2 = faad_get_ts();
#endif
#ifdef ALLOW_SMALL_FRAMELENGTH
#ifdef FIXED_POINT
/* detect non-power of 2 */
if (N & (N-1))
{
/* adjust scale for non-power of 2 MDCT */
/* 2048/1920 */
b_scale = 1;
scale = COEF_CONST(1.0666666666666667);
}
#endif
#endif
/* pre-IFFT complex multiplication */
for (k = 0; k < N4; k++)
{
ComplexMult(&IM(Z1[k]), &RE(Z1[k]),
X_in[2*k], X_in[N2 - 1 - 2*k], RE(sincos[k]), IM(sincos[k]));
}
#ifdef PROFILE
count1 = faad_get_ts();
#endif
/* complex IFFT, any non-scaling FFT can be used here */
cfftb(mdct->cfft, Z1);
#ifdef PROFILE
count1 = faad_get_ts() - count1;
#endif
/* post-IFFT complex multiplication */
for (k = 0; k < N4; k++)
{
RE(x) = RE(Z1[k]);
IM(x) = IM(Z1[k]);
ComplexMult(&IM(Z1[k]), &RE(Z1[k]),
IM(x), RE(x), RE(sincos[k]), IM(sincos[k]));
#ifdef ALLOW_SMALL_FRAMELENGTH
#ifdef FIXED_POINT
/* non-power of 2 MDCT scaling */
if (b_scale)
{
RE(Z1[k]) = MUL_C(RE(Z1[k]), scale);
IM(Z1[k]) = MUL_C(IM(Z1[k]), scale);
}
#endif
#endif
}
/* reordering */
for (k = 0; k < N8; k+=2)
{
X_out[ 2*k] = IM(Z1[N8 + k]);
X_out[ 2 + 2*k] = IM(Z1[N8 + 1 + k]);
X_out[ 1 + 2*k] = -RE(Z1[N8 - 1 - k]);
X_out[ 3 + 2*k] = -RE(Z1[N8 - 2 - k]);
X_out[N4 + 2*k] = RE(Z1[ k]);
X_out[N4 + + 2 + 2*k] = RE(Z1[ 1 + k]);
X_out[N4 + 1 + 2*k] = -IM(Z1[N4 - 1 - k]);
X_out[N4 + 3 + 2*k] = -IM(Z1[N4 - 2 - k]);
X_out[N2 + 2*k] = RE(Z1[N8 + k]);
X_out[N2 + + 2 + 2*k] = RE(Z1[N8 + 1 + k]);
X_out[N2 + 1 + 2*k] = -IM(Z1[N8 - 1 - k]);
X_out[N2 + 3 + 2*k] = -IM(Z1[N8 - 2 - k]);
X_out[N2 + N4 + 2*k] = -IM(Z1[ k]);
X_out[N2 + N4 + 2 + 2*k] = -IM(Z1[ 1 + k]);
X_out[N2 + N4 + 1 + 2*k] = RE(Z1[N4 - 1 - k]);
X_out[N2 + N4 + 3 + 2*k] = RE(Z1[N4 - 2 - k]);
}
#ifdef PROFILE
count2 = faad_get_ts() - count2;
mdct->fft_cycles += count1;
mdct->cycles += (count2 - count1);
#endif
}
#ifdef LTP_DEC
void faad_mdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
{
uint16_t k;
complex_t x;
ALIGN complex_t Z1[512];
complex_t *sincos = mdct->sincos;
uint16_t N = mdct->N;
uint16_t N2 = N >> 1;
uint16_t N4 = N >> 2;
uint16_t N8 = N >> 3;
#ifndef FIXED_POINT
real_t scale = REAL_CONST(N);
#else
real_t scale = REAL_CONST(4.0/N);
#endif
#ifdef ALLOW_SMALL_FRAMELENGTH
#ifdef FIXED_POINT
/* detect non-power of 2 */
if (N & (N-1))
{
/* adjust scale for non-power of 2 MDCT */
/* *= sqrt(2048/1920) */
scale = MUL_C(scale, COEF_CONST(1.0327955589886444));
}
#endif
#endif
/* pre-FFT complex multiplication */
for (k = 0; k < N8; k++)
{
uint16_t n = k << 1;
RE(x) = X_in[N - N4 - 1 - n] + X_in[N - N4 + n];
IM(x) = X_in[ N4 + n] - X_in[ N4 - 1 - n];
ComplexMult(&RE(Z1[k]), &IM(Z1[k]),
RE(x), IM(x), RE(sincos[k]), IM(sincos[k]));
RE(Z1[k]) = MUL_R(RE(Z1[k]), scale);
IM(Z1[k]) = MUL_R(IM(Z1[k]), scale);
RE(x) = X_in[N2 - 1 - n] - X_in[ n];
IM(x) = X_in[N2 + n] + X_in[N - 1 - n];
ComplexMult(&RE(Z1[k + N8]), &IM(Z1[k + N8]),
RE(x), IM(x), RE(sincos[k + N8]), IM(sincos[k + N8]));
RE(Z1[k + N8]) = MUL_R(RE(Z1[k + N8]), scale);
IM(Z1[k + N8]) = MUL_R(IM(Z1[k + N8]), scale);
}
/* complex FFT, any non-scaling FFT can be used here */
cfftf(mdct->cfft, Z1);
/* post-FFT complex multiplication */
for (k = 0; k < N4; k++)
{
uint16_t n = k << 1;
ComplexMult(&RE(x), &IM(x),
RE(Z1[k]), IM(Z1[k]), RE(sincos[k]), IM(sincos[k]));
X_out[ n] = -RE(x);
X_out[N2 - 1 - n] = IM(x);
X_out[N2 + n] = -IM(x);
X_out[N - 1 - n] = RE(x);
}
}
#endif