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![Nedeljko Babic](/assets/img/avatar_default.png)
Iterative implementation of 32 bit fixed point split-radix FFT. Max FFT that can be calculated currently is 2^12. Signed-off-by: Nedeljko Babic <nbabic@mips.com> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
500 lines
13 KiB
C
500 lines
13 KiB
C
/*
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* (c) 2002 Fabrice Bellard
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* FFT and MDCT tests.
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*/
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#include "libavutil/cpu.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/lfg.h"
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#include "libavutil/log.h"
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#include "libavutil/time.h"
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#include "fft.h"
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#if CONFIG_FFT_FLOAT
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#include "dct.h"
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#include "rdft.h"
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#endif
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#include <math.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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/* reference fft */
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#define MUL16(a,b) ((a) * (b))
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#define CMAC(pre, pim, are, aim, bre, bim) \
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{\
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pre += (MUL16(are, bre) - MUL16(aim, bim));\
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pim += (MUL16(are, bim) + MUL16(bre, aim));\
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}
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#if CONFIG_FFT_FLOAT
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# define RANGE 1.0
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# define REF_SCALE(x, bits) (x)
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# define FMT "%10.6f"
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#elif CONFIG_FFT_FIXED_32
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# define RANGE 8388608
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# define REF_SCALE(x, bits) (x)
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# define FMT "%6d"
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#else
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# define RANGE 16384
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# define REF_SCALE(x, bits) ((x) / (1<<(bits)))
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# define FMT "%6d"
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#endif
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struct {
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float re, im;
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} *exptab;
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static void fft_ref_init(int nbits, int inverse)
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{
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int n, i;
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double c1, s1, alpha;
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n = 1 << nbits;
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exptab = av_malloc((n / 2) * sizeof(*exptab));
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for (i = 0; i < (n/2); i++) {
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alpha = 2 * M_PI * (float)i / (float)n;
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c1 = cos(alpha);
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s1 = sin(alpha);
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if (!inverse)
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s1 = -s1;
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exptab[i].re = c1;
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exptab[i].im = s1;
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}
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}
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static void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
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{
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int n, i, j, k, n2;
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double tmp_re, tmp_im, s, c;
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FFTComplex *q;
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n = 1 << nbits;
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n2 = n >> 1;
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for (i = 0; i < n; i++) {
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tmp_re = 0;
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tmp_im = 0;
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q = tab;
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for (j = 0; j < n; j++) {
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k = (i * j) & (n - 1);
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if (k >= n2) {
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c = -exptab[k - n2].re;
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s = -exptab[k - n2].im;
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} else {
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c = exptab[k].re;
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s = exptab[k].im;
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}
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CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
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q++;
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}
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tabr[i].re = REF_SCALE(tmp_re, nbits);
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tabr[i].im = REF_SCALE(tmp_im, nbits);
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}
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}
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static void imdct_ref(FFTSample *out, FFTSample *in, int nbits)
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{
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int n = 1<<nbits;
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int k, i, a;
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double sum, f;
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for (i = 0; i < n; i++) {
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sum = 0;
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for (k = 0; k < n/2; k++) {
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a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
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f = cos(M_PI * a / (double)(2 * n));
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sum += f * in[k];
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}
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out[i] = REF_SCALE(-sum, nbits - 2);
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}
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}
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/* NOTE: no normalisation by 1 / N is done */
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static void mdct_ref(FFTSample *output, FFTSample *input, int nbits)
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{
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int n = 1<<nbits;
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int k, i;
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double a, s;
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/* do it by hand */
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for (k = 0; k < n/2; k++) {
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s = 0;
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for (i = 0; i < n; i++) {
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a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
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s += input[i] * cos(a);
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}
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output[k] = REF_SCALE(s, nbits - 1);
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}
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}
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#if CONFIG_FFT_FLOAT
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static void idct_ref(FFTSample *output, FFTSample *input, int nbits)
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{
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int n = 1<<nbits;
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int k, i;
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double a, s;
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/* do it by hand */
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for (i = 0; i < n; i++) {
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s = 0.5 * input[0];
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for (k = 1; k < n; k++) {
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a = M_PI*k*(i+0.5) / n;
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s += input[k] * cos(a);
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}
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output[i] = 2 * s / n;
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}
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}
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static void dct_ref(FFTSample *output, FFTSample *input, int nbits)
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{
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int n = 1<<nbits;
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int k, i;
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double a, s;
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/* do it by hand */
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for (k = 0; k < n; k++) {
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s = 0;
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for (i = 0; i < n; i++) {
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a = M_PI*k*(i+0.5) / n;
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s += input[i] * cos(a);
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}
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output[k] = s;
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}
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}
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#endif
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static FFTSample frandom(AVLFG *prng)
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{
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return (int16_t)av_lfg_get(prng) / 32768.0 * RANGE;
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}
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static int check_diff(FFTSample *tab1, FFTSample *tab2, int n, double scale)
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{
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int i;
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double max= 0;
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double error= 0;
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int err = 0;
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for (i = 0; i < n; i++) {
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double e = fabsf(tab1[i] - (tab2[i] / scale)) / RANGE;
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if (e >= 1e-3) {
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av_log(NULL, AV_LOG_ERROR, "ERROR %5d: "FMT" "FMT"\n",
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i, tab1[i], tab2[i]);
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err = 1;
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}
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error+= e*e;
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if(e>max) max= e;
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}
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av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error/n));
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return err;
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}
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static void help(void)
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{
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av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n"
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"-h print this help\n"
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"-s speed test\n"
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"-m (I)MDCT test\n"
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"-d (I)DCT test\n"
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"-r (I)RDFT test\n"
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"-i inverse transform test\n"
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"-n b set the transform size to 2^b\n"
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"-f x set scale factor for output data of (I)MDCT to x\n"
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);
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}
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enum tf_transform {
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TRANSFORM_FFT,
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TRANSFORM_MDCT,
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TRANSFORM_RDFT,
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TRANSFORM_DCT,
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};
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#if !HAVE_GETOPT
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#include "compat/getopt.c"
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#endif
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int main(int argc, char **argv)
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{
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FFTComplex *tab, *tab1, *tab_ref;
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FFTSample *tab2;
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int it, i, c;
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int cpuflags;
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int do_speed = 0;
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int err = 1;
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enum tf_transform transform = TRANSFORM_FFT;
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int do_inverse = 0;
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FFTContext s1, *s = &s1;
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FFTContext m1, *m = &m1;
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#if CONFIG_FFT_FLOAT
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RDFTContext r1, *r = &r1;
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DCTContext d1, *d = &d1;
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int fft_size_2;
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#endif
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int fft_nbits, fft_size;
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double scale = 1.0;
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AVLFG prng;
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av_lfg_init(&prng, 1);
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fft_nbits = 9;
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for(;;) {
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c = getopt(argc, argv, "hsimrdn:f:c:");
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if (c == -1)
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break;
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switch(c) {
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case 'h':
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help();
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return 1;
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case 's':
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do_speed = 1;
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break;
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case 'i':
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do_inverse = 1;
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break;
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case 'm':
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transform = TRANSFORM_MDCT;
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break;
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case 'r':
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transform = TRANSFORM_RDFT;
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break;
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case 'd':
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transform = TRANSFORM_DCT;
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break;
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case 'n':
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fft_nbits = atoi(optarg);
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break;
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case 'f':
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scale = atof(optarg);
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break;
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case 'c':
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cpuflags = av_get_cpu_flags();
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if (av_parse_cpu_caps(&cpuflags, optarg) < 0)
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return 1;
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av_force_cpu_flags(cpuflags);
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break;
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}
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}
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fft_size = 1 << fft_nbits;
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tab = av_malloc(fft_size * sizeof(FFTComplex));
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tab1 = av_malloc(fft_size * sizeof(FFTComplex));
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tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
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tab2 = av_malloc(fft_size * sizeof(FFTSample));
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switch (transform) {
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case TRANSFORM_MDCT:
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av_log(NULL, AV_LOG_INFO,"Scale factor is set to %f\n", scale);
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if (do_inverse)
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av_log(NULL, AV_LOG_INFO,"IMDCT");
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else
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av_log(NULL, AV_LOG_INFO,"MDCT");
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ff_mdct_init(m, fft_nbits, do_inverse, scale);
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break;
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case TRANSFORM_FFT:
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if (do_inverse)
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av_log(NULL, AV_LOG_INFO,"IFFT");
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else
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av_log(NULL, AV_LOG_INFO,"FFT");
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ff_fft_init(s, fft_nbits, do_inverse);
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fft_ref_init(fft_nbits, do_inverse);
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break;
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#if CONFIG_FFT_FLOAT
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case TRANSFORM_RDFT:
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if (do_inverse)
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av_log(NULL, AV_LOG_INFO,"IDFT_C2R");
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else
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av_log(NULL, AV_LOG_INFO,"DFT_R2C");
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ff_rdft_init(r, fft_nbits, do_inverse ? IDFT_C2R : DFT_R2C);
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fft_ref_init(fft_nbits, do_inverse);
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break;
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case TRANSFORM_DCT:
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if (do_inverse)
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av_log(NULL, AV_LOG_INFO,"DCT_III");
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else
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av_log(NULL, AV_LOG_INFO,"DCT_II");
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ff_dct_init(d, fft_nbits, do_inverse ? DCT_III : DCT_II);
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break;
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#endif
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default:
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av_log(NULL, AV_LOG_ERROR, "Requested transform not supported\n");
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return 1;
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}
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av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);
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/* generate random data */
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for (i = 0; i < fft_size; i++) {
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tab1[i].re = frandom(&prng);
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tab1[i].im = frandom(&prng);
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}
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/* checking result */
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av_log(NULL, AV_LOG_INFO,"Checking...\n");
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switch (transform) {
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case TRANSFORM_MDCT:
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if (do_inverse) {
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imdct_ref((FFTSample *)tab_ref, (FFTSample *)tab1, fft_nbits);
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m->imdct_calc(m, tab2, (FFTSample *)tab1);
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err = check_diff((FFTSample *)tab_ref, tab2, fft_size, scale);
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} else {
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mdct_ref((FFTSample *)tab_ref, (FFTSample *)tab1, fft_nbits);
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m->mdct_calc(m, tab2, (FFTSample *)tab1);
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err = check_diff((FFTSample *)tab_ref, tab2, fft_size / 2, scale);
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}
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break;
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case TRANSFORM_FFT:
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memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
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s->fft_permute(s, tab);
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s->fft_calc(s, tab);
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fft_ref(tab_ref, tab1, fft_nbits);
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err = check_diff((FFTSample *)tab_ref, (FFTSample *)tab, fft_size * 2, 1.0);
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break;
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#if CONFIG_FFT_FLOAT
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case TRANSFORM_RDFT:
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fft_size_2 = fft_size >> 1;
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if (do_inverse) {
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tab1[ 0].im = 0;
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tab1[fft_size_2].im = 0;
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for (i = 1; i < fft_size_2; i++) {
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tab1[fft_size_2+i].re = tab1[fft_size_2-i].re;
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tab1[fft_size_2+i].im = -tab1[fft_size_2-i].im;
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}
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memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
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tab2[1] = tab1[fft_size_2].re;
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r->rdft_calc(r, tab2);
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fft_ref(tab_ref, tab1, fft_nbits);
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for (i = 0; i < fft_size; i++) {
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tab[i].re = tab2[i];
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tab[i].im = 0;
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}
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err = check_diff((float *)tab_ref, (float *)tab, fft_size * 2, 0.5);
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} else {
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for (i = 0; i < fft_size; i++) {
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tab2[i] = tab1[i].re;
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tab1[i].im = 0;
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}
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r->rdft_calc(r, tab2);
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fft_ref(tab_ref, tab1, fft_nbits);
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tab_ref[0].im = tab_ref[fft_size_2].re;
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err = check_diff((float *)tab_ref, (float *)tab2, fft_size, 1.0);
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}
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break;
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case TRANSFORM_DCT:
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memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
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d->dct_calc(d, (FFTSample *)tab);
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if (do_inverse) {
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idct_ref((FFTSample*)tab_ref, (FFTSample *)tab1, fft_nbits);
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} else {
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dct_ref((FFTSample*)tab_ref, (FFTSample *)tab1, fft_nbits);
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}
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err = check_diff((float *)tab_ref, (float *)tab, fft_size, 1.0);
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break;
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#endif
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}
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/* do a speed test */
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if (do_speed) {
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int64_t time_start, duration;
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int nb_its;
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av_log(NULL, AV_LOG_INFO,"Speed test...\n");
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/* we measure during about 1 seconds */
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nb_its = 1;
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for(;;) {
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time_start = av_gettime();
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for (it = 0; it < nb_its; it++) {
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switch (transform) {
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case TRANSFORM_MDCT:
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if (do_inverse) {
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m->imdct_calc(m, (FFTSample *)tab, (FFTSample *)tab1);
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} else {
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m->mdct_calc(m, (FFTSample *)tab, (FFTSample *)tab1);
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}
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break;
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case TRANSFORM_FFT:
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memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
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s->fft_calc(s, tab);
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break;
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#if CONFIG_FFT_FLOAT
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case TRANSFORM_RDFT:
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memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
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r->rdft_calc(r, tab2);
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break;
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case TRANSFORM_DCT:
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memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
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d->dct_calc(d, tab2);
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break;
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#endif
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}
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}
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duration = av_gettime() - time_start;
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if (duration >= 1000000)
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break;
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nb_its *= 2;
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}
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av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
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(double)duration / nb_its,
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(double)duration / 1000000.0,
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nb_its);
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}
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switch (transform) {
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case TRANSFORM_MDCT:
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ff_mdct_end(m);
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break;
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case TRANSFORM_FFT:
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ff_fft_end(s);
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break;
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#if CONFIG_FFT_FLOAT
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case TRANSFORM_RDFT:
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ff_rdft_end(r);
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break;
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case TRANSFORM_DCT:
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ff_dct_end(d);
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break;
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#endif
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}
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av_free(tab);
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av_free(tab1);
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av_free(tab2);
|
|
av_free(tab_ref);
|
|
av_free(exptab);
|
|
|
|
return err;
|
|
}
|