void vp9_init_dequantizer(VP9_COMMON *pc) {
int q;
for (q = 0; q < QINDEX_RANGE; q++) {
// DC value
pc->y_dequant[q][0] = vp9_dc_quant(q, pc->y_dc_delta_q);
pc->uv_dequant[q][0] = vp9_dc_quant(q, pc->uv_dc_delta_q);
// AC values
pc->y_dequant[q][1] = vp9_ac_quant(q, 0);
pc->uv_dequant[q][1] = vp9_ac_quant(q, pc->uv_ac_delta_q);
}
}
// These functions use formulaic calculations to make playing with the
// quantizer tables easier. If necessary they can be replaced by lookup
// tables if and when things settle down in the experimental bitstream
double vp9_convert_qindex_to_q(int qindex) {
// Convert the index to a real Q value (scaled down to match old Q values)
return vp9_ac_quant(qindex, 0) / 4.0;
}
static int get_aq_c_strength(int q_index, vpx_bit_depth_t bit_depth) {
// Approximate base quatizer (truncated to int)
const int base_quant = vp9_ac_quant(q_index, 0, bit_depth) / 4;
return (base_quant > 10) + (base_quant > 25);
}
