s->decoded[channel][i] += sum >> qlevel;
}
} else {
- int sum;
- for (i = pred_order; i < s->blocksize; i++)
+ for (i = pred_order; i < s->blocksize-1; i += 2)
{
- sum = 0;
+ int c = coeffs[pred_order-1];
+ int s0 = c * s->decoded[channel][i-pred_order];
+ int s1 = 0;
+ for (j = pred_order-1; j > 0; j--)
+ {
+ int d = s->decoded[channel][i-j];
+ s1 += c*d;
+ c = coeffs[j-1];
+ s0 += c*d;
+ }
+ s0 = s->decoded[channel][i] += s0 >> qlevel;
+ s1 += c * s0;
+ s->decoded[channel][i+1] += s1 >> qlevel;
+ }
+ if (i < s->blocksize)
+ {
+ int sum = 0;
for (j = 0; j < pred_order; j++)
sum += coeffs[j] * s->decoded[channel][i-j-1];
s->decoded[channel][i] += sum >> qlevel;