From 519adfbaae5933ec18d2e3cb77e690e36cd49916 Mon Sep 17 00:00:00 2001 From: Mohamed Tarek Date: Mon, 10 Aug 2009 14:46:31 +0000 Subject: Import libatrac from ffmpeg and modify librm to support ATRAC3. The decoder is still in floating point. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22235 a1c6a512-1295-4272-9138-f99709370657 --- apps/codecs/libatrac/mdct.c | 245 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 245 insertions(+) create mode 100644 apps/codecs/libatrac/mdct.c (limited to 'apps/codecs/libatrac/mdct.c') diff --git a/apps/codecs/libatrac/mdct.c b/apps/codecs/libatrac/mdct.c new file mode 100644 index 0000000000..670b6d381e --- /dev/null +++ b/apps/codecs/libatrac/mdct.c @@ -0,0 +1,245 @@ +/* + * 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 "dsputil.h" + +#ifndef M_E +#define M_E 2.7182818284590452354 /* e */ +#endif +#ifndef M_LN2 +#define M_LN2 0.69314718055994530942 /* log_e 2 */ +#endif +#ifndef M_LN10 +#define M_LN10 2.30258509299404568402 /* log_e 10 */ +#endif +#ifndef M_PI +#define M_PI 3.14159265358979323846 /* pi */ +#endif +#ifndef M_SQRT1_2 +#define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */ +#endif + +/** + * @file libavcodec/mdct.c + * 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))); +} + +/** + * init MDCT or IMDCT computation. + */ +av_cold int ff_mdct_init(MDCTContext *s, int nbits, int inverse) +{ + int n, n4, i; + double alpha; + + memset(s, 0, sizeof(*s)); + n = 1 << nbits; + s->nbits = nbits; + s->n = n; + n4 = n >> 2; + s->tcos = av_malloc(n4 * sizeof(FFTSample)); + if (!s->tcos) + goto fail; + s->tsin = av_malloc(n4 * sizeof(FFTSample)); + if (!s->tsin) + goto fail; + + for(i=0;itcos[i] = -cos(alpha); + s->tsin[i] = -sin(alpha); + } + if (ff_fft_init(&s->fft, s->nbits - 2, inverse) < 0) + goto fail; + return 0; + fail: + av_freep(&s->tcos); + av_freep(&s->tsin); + 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) +{ + int k, n8, n4, n2, n, j; + const uint16_t *revtab = s->fft.revtab; + const FFTSample *tcos = s->tcos; + const FFTSample *tsin = s->tsin; + const FFTSample *in1, *in2; + FFTComplex *z = (FFTComplex *)output; + + n = 1 << s->nbits; + 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; + } + ff_fft_calc(&s->fft, 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]); + 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(MDCTContext *s, FFTSample *output, const FFTSample *input) +{ + int k; + int n = 1 << s->nbits; + 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(MDCTContext *s, FFTSample *out, const FFTSample *input) +{ + int i, j, n, n8, n4, n2, n3; + FFTSample re, im; + const uint16_t *revtab = s->fft.revtab; + const FFTSample *tcos = s->tcos; + const FFTSample *tsin = s->tsin; + FFTComplex *x = (FFTComplex *)out; + + n = 1 << s->nbits; + n2 = n >> 1; + n4 = n >> 2; + n8 = n >> 3; + n3 = 3 * n4; + + /* pre rotation */ + for(i=0;ifft, x); + + /* post rotation */ + for(i=0;itcos); + av_freep(&s->tsin); + ff_fft_end(&s->fft); +} -- cgit v1.2.3