mirror of
https://github.com/pineappleEA/pineapple-src.git
synced 2024-12-05 12:48:24 -05:00
214 lines
5.5 KiB
C
Executable File
214 lines
5.5 KiB
C
Executable File
/*
|
|
* MDCT/IMDCT transforms
|
|
* Copyright (c) 2002 Fabrice Bellard
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include "libavutil/common.h"
|
|
#include "libavutil/libm.h"
|
|
#include "libavutil/mathematics.h"
|
|
#include "fft.h"
|
|
#include "fft-internal.h"
|
|
|
|
/**
|
|
* @file
|
|
* MDCT/IMDCT transforms.
|
|
*/
|
|
|
|
#if FFT_FLOAT
|
|
# define RSCALE(x, y) ((x) + (y))
|
|
#else
|
|
#if FFT_FIXED_32
|
|
# define RSCALE(x, y) ((int)((x) + (unsigned)(y) + 32) >> 6)
|
|
#else /* FFT_FIXED_32 */
|
|
# define RSCALE(x, y) ((int)((x) + (unsigned)(y)) >> 1)
|
|
#endif /* FFT_FIXED_32 */
|
|
#endif
|
|
|
|
/**
|
|
* init MDCT or IMDCT computation.
|
|
*/
|
|
av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
|
|
{
|
|
int n, n4, i;
|
|
double alpha, theta;
|
|
int tstep;
|
|
|
|
memset(s, 0, sizeof(*s));
|
|
n = 1 << nbits;
|
|
s->mdct_bits = nbits;
|
|
s->mdct_size = n;
|
|
n4 = n >> 2;
|
|
s->mdct_permutation = FF_MDCT_PERM_NONE;
|
|
|
|
if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
|
|
goto fail;
|
|
|
|
s->tcos = av_malloc_array(n/2, sizeof(FFTSample));
|
|
if (!s->tcos)
|
|
goto fail;
|
|
|
|
switch (s->mdct_permutation) {
|
|
case FF_MDCT_PERM_NONE:
|
|
s->tsin = s->tcos + n4;
|
|
tstep = 1;
|
|
break;
|
|
case FF_MDCT_PERM_INTERLEAVE:
|
|
s->tsin = s->tcos + 1;
|
|
tstep = 2;
|
|
break;
|
|
default:
|
|
goto fail;
|
|
}
|
|
|
|
theta = 1.0 / 8.0 + (scale < 0 ? n4 : 0);
|
|
scale = sqrt(fabs(scale));
|
|
for(i=0;i<n4;i++) {
|
|
alpha = 2 * M_PI * (i + theta) / n;
|
|
#if FFT_FIXED_32
|
|
s->tcos[i*tstep] = lrint(-cos(alpha) * 2147483648.0);
|
|
s->tsin[i*tstep] = lrint(-sin(alpha) * 2147483648.0);
|
|
#else
|
|
s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
|
|
s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
|
|
#endif
|
|
}
|
|
return 0;
|
|
fail:
|
|
ff_mdct_end(s);
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* Compute the middle half of the inverse MDCT of size N = 2^nbits,
|
|
* thus excluding the parts that can be derived by symmetry
|
|
* @param output N/2 samples
|
|
* @param input N/2 samples
|
|
*/
|
|
void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input)
|
|
{
|
|
int k, n8, n4, n2, n, j;
|
|
const uint16_t *revtab = s->revtab;
|
|
const FFTSample *tcos = s->tcos;
|
|
const FFTSample *tsin = s->tsin;
|
|
const FFTSample *in1, *in2;
|
|
FFTComplex *z = (FFTComplex *)output;
|
|
|
|
n = 1 << s->mdct_bits;
|
|
n2 = n >> 1;
|
|
n4 = n >> 2;
|
|
n8 = n >> 3;
|
|
|
|
/* pre rotation */
|
|
in1 = input;
|
|
in2 = input + n2 - 1;
|
|
for(k = 0; k < n4; k++) {
|
|
j=revtab[k];
|
|
CMUL(z[j].re, z[j].im, *in2, *in1, tcos[k], tsin[k]);
|
|
in1 += 2;
|
|
in2 -= 2;
|
|
}
|
|
s->fft_calc(s, z);
|
|
|
|
/* post rotation + reordering */
|
|
for(k = 0; k < n8; k++) {
|
|
FFTSample r0, i0, r1, i1;
|
|
CMUL(r0, i1, z[n8-k-1].im, z[n8-k-1].re, tsin[n8-k-1], tcos[n8-k-1]);
|
|
CMUL(r1, i0, z[n8+k ].im, z[n8+k ].re, tsin[n8+k ], tcos[n8+k ]);
|
|
z[n8-k-1].re = r0;
|
|
z[n8-k-1].im = i0;
|
|
z[n8+k ].re = r1;
|
|
z[n8+k ].im = i1;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Compute inverse MDCT of size N = 2^nbits
|
|
* @param output N samples
|
|
* @param input N/2 samples
|
|
*/
|
|
void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
|
|
{
|
|
int k;
|
|
int n = 1 << s->mdct_bits;
|
|
int n2 = n >> 1;
|
|
int n4 = n >> 2;
|
|
|
|
ff_imdct_half_c(s, output+n4, input);
|
|
|
|
for(k = 0; k < n4; k++) {
|
|
output[k] = -output[n2-k-1];
|
|
output[n-k-1] = output[n2+k];
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Compute MDCT of size N = 2^nbits
|
|
* @param input N samples
|
|
* @param out N/2 samples
|
|
*/
|
|
void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
|
|
{
|
|
int i, j, n, n8, n4, n2, n3;
|
|
FFTDouble re, im;
|
|
const uint16_t *revtab = s->revtab;
|
|
const FFTSample *tcos = s->tcos;
|
|
const FFTSample *tsin = s->tsin;
|
|
FFTComplex *x = (FFTComplex *)out;
|
|
|
|
n = 1 << s->mdct_bits;
|
|
n2 = n >> 1;
|
|
n4 = n >> 2;
|
|
n8 = n >> 3;
|
|
n3 = 3 * n4;
|
|
|
|
/* pre rotation */
|
|
for(i=0;i<n8;i++) {
|
|
re = RSCALE(-input[2*i+n3], - input[n3-1-2*i]);
|
|
im = RSCALE(-input[n4+2*i], + input[n4-1-2*i]);
|
|
j = revtab[i];
|
|
CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
|
|
|
|
re = RSCALE( input[2*i] , - input[n2-1-2*i]);
|
|
im = RSCALE(-input[n2+2*i], - input[ n-1-2*i]);
|
|
j = revtab[n8 + i];
|
|
CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
|
|
}
|
|
|
|
s->fft_calc(s, x);
|
|
|
|
/* post rotation */
|
|
for(i=0;i<n8;i++) {
|
|
FFTSample r0, i0, r1, i1;
|
|
CMUL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
|
|
CMUL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]);
|
|
x[n8-i-1].re = r0;
|
|
x[n8-i-1].im = i0;
|
|
x[n8+i ].re = r1;
|
|
x[n8+i ].im = i1;
|
|
}
|
|
}
|
|
|
|
av_cold void ff_mdct_end(FFTContext *s)
|
|
{
|
|
av_freep(&s->tcos);
|
|
ff_fft_end(s);
|
|
}
|