* MDCT/IMDCT transforms
* Copyright (c) 2002 Fabrice Bellard
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav 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,
+ * Libav 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
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#include "dsputil.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include "libavutil/common.h"
+#include "libavutil/mathematics.h"
+#include "fft.h"
+#include "fft-internal.h"
/**
- * @file libavcodec/mdct.c
+ * @file
* MDCT/IMDCT transforms.
*/
-// Generate a Kaiser-Bessel Derived Window.
-#define BESSEL_I0_ITER 50 // default: 50 iterations of Bessel I0 approximation
-av_cold void ff_kbd_window_init(float *window, float alpha, int n)
-{
- int i, j;
- double sum = 0.0, bessel, tmp;
- double local_window[n];
- double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n);
-
- for (i = 0; i < n; i++) {
- tmp = i * (n - i) * alpha2;
- bessel = 1.0;
- for (j = BESSEL_I0_ITER; j > 0; j--)
- bessel = bessel * tmp / (j * j) + 1;
- sum += bessel;
- local_window[i] = sum;
- }
-
- sum++;
- for (i = 0; i < n; i++)
- window[i] = sqrt(local_window[i] / sum);
-}
-
-DECLARE_ALIGNED(16, float, ff_sine_128 [ 128]);
-DECLARE_ALIGNED(16, float, ff_sine_256 [ 256]);
-DECLARE_ALIGNED(16, float, ff_sine_512 [ 512]);
-DECLARE_ALIGNED(16, float, ff_sine_1024[1024]);
-DECLARE_ALIGNED(16, float, ff_sine_2048[2048]);
-DECLARE_ALIGNED(16, float, ff_sine_4096[4096]);
-float *ff_sine_windows[6] = {
- ff_sine_128, ff_sine_256, ff_sine_512, ff_sine_1024, ff_sine_2048, ff_sine_4096
-};
-
-// Generate a sine window.
-av_cold void ff_sine_window_init(float *window, int n) {
- int i;
- for(i = 0; i < n; i++)
- window[i] = sinf((i + 0.5) * (M_PI / (2.0 * n)));
-}
+#if CONFIG_FFT_FLOAT
+# define RSCALE(x) (x)
+#else
+# define RSCALE(x) ((x) >> 1)
+#endif
/**
* init MDCT or IMDCT computation.
*/
-av_cold int ff_mdct_init(MDCTContext *s, int nbits, int inverse)
+av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
{
int n, n4, i;
- double alpha;
+ double alpha, theta;
+ int tstep;
memset(s, 0, sizeof(*s));
n = 1 << nbits;
- s->nbits = nbits;
- s->n = n;
+ s->mdct_bits = nbits;
+ s->mdct_size = n;
n4 = n >> 2;
- s->tcos = av_malloc(n4 * sizeof(FFTSample));
+ s->mdct_permutation = FF_MDCT_PERM_NONE;
+
+ if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
+ goto fail;
+
+ s->tcos = av_malloc(n/2 * sizeof(FFTSample));
if (!s->tcos)
goto fail;
- s->tsin = av_malloc(n4 * sizeof(FFTSample));
- if (!s->tsin)
+
+ 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 + 1.0 / 8.0) / n;
- s->tcos[i] = -cos(alpha);
- s->tsin[i] = -sin(alpha);
+ alpha = 2 * M_PI * (i + theta) / n;
+ s->tcos[i*tstep] = FIX15(-cos(alpha) * scale);
+ s->tsin[i*tstep] = FIX15(-sin(alpha) * scale);
}
- if (ff_fft_init(&s->fft, s->nbits - 2, inverse) < 0)
- goto fail;
return 0;
fail:
- av_freep(&s->tcos);
- av_freep(&s->tsin);
+ ff_mdct_end(s);
return -1;
}
-/* complex multiplication: p = a * b */
-#define CMUL(pre, pim, are, aim, bre, bim) \
-{\
- FFTSample _are = (are);\
- FFTSample _aim = (aim);\
- FFTSample _bre = (bre);\
- FFTSample _bim = (bim);\
- (pre) = _are * _bre - _aim * _bim;\
- (pim) = _are * _bim + _aim * _bre;\
-}
-
/**
* 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(MDCTContext *s, FFTSample *output, const FFTSample *input)
+void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input)
{
int k, n8, n4, n2, n, j;
- const uint16_t *revtab = s->fft.revtab;
+ 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->nbits;
+ n = 1 << s->mdct_bits;
n2 = n >> 1;
n4 = n >> 2;
n8 = n >> 3;
in1 += 2;
in2 -= 2;
}
- ff_fft_calc(&s->fft, z);
+ s->fft_calc(s, z);
/* post rotation + reordering */
- output += n4;
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]);
* @param output N samples
* @param input N/2 samples
*/
-void ff_imdct_calc_c(MDCTContext *s, FFTSample *output, const FFTSample *input)
+void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input)
{
int k;
- int n = 1 << s->nbits;
+ int n = 1 << s->mdct_bits;
int n2 = n >> 1;
int n4 = n >> 2;
* @param input N samples
* @param out N/2 samples
*/
-void ff_mdct_calc(MDCTContext *s, FFTSample *out, const FFTSample *input)
+void ff_mdct_calc_c(FFTContext *s, FFTSample *out, const FFTSample *input)
{
int i, j, n, n8, n4, n2, n3;
- FFTSample re, im;
- const uint16_t *revtab = s->fft.revtab;
+ 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->nbits;
+ n = 1 << s->mdct_bits;
n2 = n >> 1;
n4 = n >> 2;
n8 = n >> 3;
/* pre rotation */
for(i=0;i<n8;i++) {
- re = -input[2*i+3*n4] - input[n3-1-2*i];
- im = -input[n4+2*i] + input[n4-1-2*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 = input[2*i] - input[n2-1-2*i];
- im = -(input[n2+2*i] + input[n-1-2*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]);
}
- ff_fft_calc(&s->fft, x);
+ s->fft_calc(s, x);
/* post rotation */
for(i=0;i<n8;i++) {
}
}
-av_cold void ff_mdct_end(MDCTContext *s)
+av_cold void ff_mdct_end(FFTContext *s)
{
av_freep(&s->tcos);
- av_freep(&s->tsin);
- ff_fft_end(&s->fft);
+ ff_fft_end(s);
}
projects / ffmpeg / blobdiff