From 5f9f6629fa88356e5735f83b09b9fa6623de9640 Mon Sep 17 00:00:00 2001 From: Mohamed Tarek Date: Sat, 7 Aug 2010 11:42:00 +0000 Subject: Initial commit for a WMA Voice decoder; Import a minimal set of files for libwmavoice from ffmpeg r24734 dated 2010-Aug-07. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27740 a1c6a512-1295-4272-9138-f99709370657 --- apps/codecs/libwmavoice/mdct.c | 234 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 234 insertions(+) create mode 100644 apps/codecs/libwmavoice/mdct.c (limited to 'apps/codecs/libwmavoice/mdct.c') diff --git a/apps/codecs/libwmavoice/mdct.c b/apps/codecs/libwmavoice/mdct.c new file mode 100644 index 0000000000..c511188d22 --- /dev/null +++ b/apps/codecs/libwmavoice/mdct.c @@ -0,0 +1,234 @@ +/* + * 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 +#include +#include "libavutil/common.h" +#include "libavutil/mathematics.h" +#include "fft.h" + +/** + * @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[FF_KBD_WINDOW_MAX]; + double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n); + + assert(n <= FF_KBD_WINDOW_MAX); + + 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); +} + +#include "mdct_tablegen.h" + +/** + * 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->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; + + switch (s->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;itcos[i*tstep] = -cos(alpha) * scale; + s->tsin[i*tstep] = -sin(alpha) * scale; + } + return 0; + fail: + 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(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; + } + ff_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; + FFTSample 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;itcos); + ff_fft_end(s); +} -- cgit v1.2.3