void ff_mdct_calcw_c(FFTContext *s, FFTDouble *out, const FFTSample *input) { int i, j, n, n8, n4, n2, n3; FFTDouble re, im; const uint16_t *revtab = s->revtab; const FFTSample *tcos = s->tcos; const FFTSample *tsin = s->tsin; FFTComplex *x = s->tmp_buf; FFTDComplex *o = (FFTDComplex *)out; n = 1 << s->mdct_bits; n2 = n >> 1; n4 = n >> 2; n8 = n >> 3; n3 = 3 * n4; /* pre rotation */ for(i=0;i<n8;i++) { re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]); im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]); j = revtab[i]; CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]); re = RSCALE( input[2*i] - input[n2-1-2*i]); im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]); j = revtab[n8 + i]; CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]); } s->fft_calc(s, x); /* post rotation */ for(i=0;i<n8;i++) { FFTDouble r0, i0, r1, i1; CMULL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]); CMULL(i0, r1, x[n8+i ].re, x[n8+i ].im, -tsin[n8+i ], -tcos[n8+i ]); o[n8-i-1].re = r0; o[n8-i-1].im = i0; o[n8+i ].re = r1; o[n8+i ].im = i1; } }