-static inline void ff_aac_tableinit(void)
-{
- int i;
-
- /* 2^(i/16) for 0 <= i <= 15 */
- static const float exp2_lut[] = {
- 1.00000000000000000000,
- 1.04427378242741384032,
- 1.09050773266525765921,
- 1.13878863475669165370,
- 1.18920711500272106672,
- 1.24185781207348404859,
- 1.29683955465100966593,
- 1.35425554693689272830,
- 1.41421356237309504880,
- 1.47682614593949931139,
- 1.54221082540794082361,
- 1.61049033194925430818,
- 1.68179283050742908606,
- 1.75625216037329948311,
- 1.83400808640934246349,
- 1.91520656139714729387,
- };
- float t1 = 8.8817841970012523233890533447265625e-16; // 2^(-50)
- float t2 = 3.63797880709171295166015625e-12; // 2^(-38)
- int t1_inc_cur, t2_inc_cur;
- int t1_inc_prev = 0;
- int t2_inc_prev = 8;
-
- for (i = 0; i < 428; i++) {
- t1_inc_cur = 4 * (i % 4);
- t2_inc_cur = (8 + 3*i) % 16;
- if (t1_inc_cur < t1_inc_prev)
- t1 *= 2;
- if (t2_inc_cur < t2_inc_prev)
- t2 *= 2;
- // A much more efficient and accurate way of doing:
- // ff_aac_pow2sf_tab[i] = pow(2, (i - POW_SF2_ZERO) / 4.0);
- // ff_aac_pow34sf_tab[i] = pow(ff_aac_pow2sf_tab[i], 3.0/4.0);
- ff_aac_pow2sf_tab[i] = t1 * exp2_lut[t1_inc_cur];
- ff_aac_pow34sf_tab[i] = t2 * exp2_lut[t2_inc_cur];
- t1_inc_prev = t1_inc_cur;
- t2_inc_prev = t2_inc_cur;
- }
-}