av_cold int ff_dct_init(DCTContext *s, int nbits, enum DCTTransformType inverse) { int n = 1 << nbits; int i; s->nbits = nbits; s->inverse = inverse; ff_init_ff_cos_tabs(nbits+2); s->costab = ff_cos_tabs[nbits+2]; s->csc2 = av_malloc(n/2 * sizeof(FFTSample)); if (ff_rdft_init(&s->rdft, nbits, inverse == DCT_III) < 0) { av_free(s->csc2); return -1; } for (i = 0; i < n/2; i++) s->csc2[i] = 0.5 / sin((M_PI / (2*n) * (2*i + 1))); switch(inverse) { case DCT_I : s->dct_calc = ff_dct_calc_I_c; break; case DCT_II : s->dct_calc = ff_dct_calc_II_c ; break; case DCT_III: s->dct_calc = ff_dct_calc_III_c; break; case DST_I : s->dct_calc = ff_dst_calc_I_c; break; } if (inverse == DCT_II && nbits == 5) s->dct_calc = dct32_func; s->dct32 = dct32; if (HAVE_MMX) ff_dct_init_mmx(s); return 0; }