av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
{
int i, j, n;
if (nbits < 2 || nbits > 16)
goto fail;
s->nbits = nbits;
n = 1 << nbits;
s->revtab = av_malloc(n * sizeof(uint16_t));
if (!s->revtab)
goto fail;
s->tmp_buf = av_malloc(n * sizeof(FFTComplex));
if (!s->tmp_buf)
goto fail;
s->inverse = inverse;
s->fft_permute = ff_fft_permute_c;
s->fft_calc = ff_fft_calc_c;
#if CONFIG_MDCT
s->imdct_calc = ff_imdct_calc_c;
s->imdct_half = ff_imdct_half_c;
s->mdct_calc = ff_mdct_calc_c;
#endif
#if ARCH_ARM
ff_fft_init_arm(s);
#endif
#if HAVE_ALTIVEC
ff_fft_init_altivec(s);
#endif
#if HAVE_MMX
ff_fft_init_mmx(s);
#endif
for(j=4; j<=nbits; j++) {
ff_init_ff_cos_tabs(j);
}
for(i=0; i<n; i++)
s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = i;
return 0;
fail:
av_freep(&s->revtab);
av_freep(&s->tmp_buf);
return -1;
}
av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
{
int i, j, m, n;
float alpha, c1, s1, s2;
int av_unused has_vectors;
if (nbits < 2 || nbits > 16)
goto fail;
s->nbits = nbits;
n = 1 << nbits;
s->tmp_buf = NULL;
s->exptab = av_malloc((n / 2) * sizeof(FFTComplex));
if (!s->exptab)
goto fail;
s->revtab = av_malloc(n * sizeof(uint16_t));
if (!s->revtab)
goto fail;
s->inverse = inverse;
s2 = inverse ? 1.0 : -1.0;
s->fft_permute = ff_fft_permute_c;
s->fft_calc = ff_fft_calc_c;
#if CONFIG_MDCT
s->imdct_calc = ff_imdct_calc_c;
s->imdct_half = ff_imdct_half_c;
s->mdct_calc = ff_mdct_calc_c;
#endif
s->exptab1 = NULL;
s->split_radix = 1;
if (ARCH_ARM) ff_fft_init_arm(s);
if (HAVE_ALTIVEC) ff_fft_init_altivec(s);
if (HAVE_MMX) ff_fft_init_mmx(s);
if (s->split_radix) {
for(j=4; j<=nbits; j++) {
ff_init_ff_cos_tabs(j);
}
for(i=0; i<n; i++)
s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = i;
s->tmp_buf = av_malloc(n * sizeof(FFTComplex));
} else {
int np, nblocks, np2, l;
FFTComplex *q;
for(i=0; i<(n/2); i++) {
alpha = 2 * M_PI * (float)i / (float)n;
c1 = cos(alpha);
s1 = sin(alpha) * s2;
s->exptab[i].re = c1;
s->exptab[i].im = s1;
}
np = 1 << nbits;
nblocks = np >> 3;
np2 = np >> 1;
s->exptab1 = av_malloc(np * 2 * sizeof(FFTComplex));
if (!s->exptab1)
goto fail;
q = s->exptab1;
do {
for(l = 0; l < np2; l += 2 * nblocks) {
*q++ = s->exptab[l];
*q++ = s->exptab[l + nblocks];
q->re = -s->exptab[l].im;
q->im = s->exptab[l].re;
q++;
q->re = -s->exptab[l + nblocks].im;
q->im = s->exptab[l + nblocks].re;
q++;
}
nblocks = nblocks >> 1;
} while (nblocks != 0);
av_freep(&s->exptab);
/* compute bit reverse table */
for(i=0;i<n;i++) {
m=0;
for(j=0;j<nbits;j++) {
m |= ((i >> j) & 1) << (nbits-j-1);
}
s->revtab[i]=m;
}
}
return 0;
fail:
av_freep(&s->revtab);
av_freep(&s->exptab);
av_freep(&s->exptab1);
av_freep(&s->tmp_buf);
return -1;
}