PeerStreamer

/**

 * @file fft-test.c

 * FFT and MDCT tests.

 */

#include "dsputil.h"

#include <math.h>

#include <unistd.h>

#include <sys/time.h>

int mm_flags;

/* reference fft */

#define MUL16(a,b) ((a) * (b))

#define CMAC(pre, pim, are, aim, bre, bim) \

{\

   pre += (MUL16(are, bre) - MUL16(aim, bim));\

   pim += (MUL16(are, bim) + MUL16(bre, aim));\

}

FFTComplex *exptab;

void fft_ref_init(int nbits, int inverse)

{

    int n, i;

    float c1, s1, alpha;

    n = 1 << nbits;

    exptab = av_malloc((n / 2) * sizeof(FFTComplex));

    for(i=0;i<(n/2);i++) {

        alpha = 2 * M_PI * (float)i / (float)n;

        c1 = cos(alpha);

        s1 = sin(alpha);

        if (!inverse)

            s1 = -s1;

        exptab[i].re = c1;

        exptab[i].im = s1;

    }

}

void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)

{

    int n, i, j, k, n2;

    float tmp_re, tmp_im, s, c;

    FFTComplex *q;

    n = 1 << nbits;

    n2 = n >> 1;

    for(i=0;i<n;i++) {

        tmp_re = 0;

        tmp_im = 0;

        q = tab;

        for(j=0;j<n;j++) {

            k = (i * j) & (n - 1);

            if (k >= n2) {

                c = -exptab[k - n2].re;

                s = -exptab[k - n2].im;

            } else {

                c = exptab[k].re;

                s = exptab[k].im;

            }

            CMAC(tmp_re, tmp_im, c, s, q->re, q->im);

            q++;

        }

        tabr[i].re = tmp_re;

        tabr[i].im = tmp_im;

    }

}

void imdct_ref(float *out, float *in, int n)

{

    int k, i, a;

    float sum, f;

    for(i=0;i<n;i++) {

        sum = 0;

        for(k=0;k<n/2;k++) {

            a = (2 * i + 1 + (n / 2)) * (2 * k + 1);

            f = cos(M_PI * a / (double)(2 * n));

            sum += f * in[k];

        }

        out[i] = -sum;

    }

}

/* NOTE: no normalisation by 1 / N is done */

void mdct_ref(float *output, float *input, int n)

{

    int k, i;

    float a, s;

    /* do it by hand */

    for(k=0;k<n/2;k++) {

        s = 0;

        for(i=0;i<n;i++) {

            a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));

            s += input[i] * cos(a);

        }

        output[k] = s;

    }

}

float frandom(void)

{

    return (float)((random() & 0xffff) - 32768) / 32768.0;

}

int64_t gettime(void)

{

    struct timeval tv;

    gettimeofday(&tv,NULL);

    return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;

}

void check_diff(float *tab1, float *tab2, int n)

{

    int i;

    for(i=0;i<n;i++) {

        if (fabsf(tab1[i] - tab2[i]) >= 1e-3) {

            printf("ERROR %d: %f %f\n", 

                   i, tab1[i], tab2[i]);

        }

    }

}

void help(void)

{

    printf("usage: fft-test [-h] [-s] [-i] [-n b]\n"

           "-h     print this help\n"

           "-s     speed test\n"

           "-m     (I)MDCT test\n"

           "-i     inverse transform test\n"

           "-n b   set the transform size to 2^b\n"

           );

    exit(1);

}

int main(int argc, char **argv)

{

    FFTComplex *tab, *tab1, *tab_ref;

    FFTSample *tabtmp, *tab2;

    int it, i, c;

    int do_speed = 0;

    int do_mdct = 0;

    int do_inverse = 0;

    FFTContext s1, *s = &s1;

    MDCTContext m1, *m = &m1;

    int fft_nbits, fft_size;

    mm_flags = 0;

    fft_nbits = 9;

    for(;;) {

        c = getopt(argc, argv, "hsimn:");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            break;

        case 's':

            do_speed = 1;

            break;

        case 'i':

            do_inverse = 1;

            break;

        case 'm':

            do_mdct = 1;

            break;

        case 'n':

            fft_nbits = atoi(optarg);

            break;

        }

    }

    fft_size = 1 << fft_nbits;

    tab = av_malloc(fft_size * sizeof(FFTComplex));

    tab1 = av_malloc(fft_size * sizeof(FFTComplex));

    tab_ref = av_malloc(fft_size * sizeof(FFTComplex));

    tabtmp = av_malloc(fft_size / 2 * sizeof(FFTSample));

    tab2 = av_malloc(fft_size * sizeof(FFTSample));

    if (do_mdct) {

        if (do_inverse)

            printf("IMDCT");

        else

            printf("MDCT");

        ff_mdct_init(m, fft_nbits, do_inverse);

    } else {

        if (do_inverse)

            printf("IFFT");

        else

            printf("FFT");

        fft_init(s, fft_nbits, do_inverse);

        fft_ref_init(fft_nbits, do_inverse);

    }

    printf(" %d test\n", fft_size);

    /* generate random data */

    for(i=0;i<fft_size;i++) {

        tab1[i].re = frandom();

        tab1[i].im = frandom();

    }

    /* checking result */

    printf("Checking...\n");

    if (do_mdct) {

        if (do_inverse) {

            imdct_ref((float *)tab_ref, (float *)tab1, fft_size);

            ff_imdct_calc(m, tab2, (float *)tab1, tabtmp);

            check_diff((float *)tab_ref, tab2, fft_size);

        } else {

            mdct_ref((float *)tab_ref, (float *)tab1, fft_size);

            ff_mdct_calc(m, tab2, (float *)tab1, tabtmp);

            check_diff((float *)tab_ref, tab2, fft_size / 2);

        }

    } else {

        memcpy(tab, tab1, fft_size * sizeof(FFTComplex));

        fft_permute(s, tab);

        fft_calc(s, tab);

        fft_ref(tab_ref, tab1, fft_nbits);

        check_diff((float *)tab_ref, (float *)tab, fft_size * 2);

    }

    /* do a speed test */

    if (do_speed) {

        int64_t time_start, duration;

        int nb_its;

        printf("Speed test...\n");

        /* we measure during about 1 seconds */

        nb_its = 1;

        for(;;) {

            time_start = gettime();

            for(it=0;it<nb_its;it++) {

                if (do_mdct) {

                    if (do_inverse) {

                        ff_imdct_calc(m, (float *)tab, (float *)tab1, tabtmp);

                    } else {

                        ff_mdct_calc(m, (float *)tab, (float *)tab1, tabtmp);

                    }

                } else {

                    memcpy(tab, tab1, fft_size * sizeof(FFTComplex));

                    fft_calc(s, tab);

                }

            }

            duration = gettime() - time_start;

            if (duration >= 1000000)

                break;

            nb_its *= 2;

        }

        printf("time: %0.1f us/transform [total time=%0.2f s its=%d]\n", 

               (double)duration / nb_its, 

               (double)duration / 1000000.0,

               nb_its);

    }

    if (do_mdct) {

        ff_mdct_end(m);

    } else {

        fft_end(s);

    }

    return 0;

}