gamma = log(0.25) / log(1.0 - FFMIN(dist25,252.0)/255.0 - 0.00001);
- for (i = -255<<LUT_BITS; i <= 255<<LUT_BITS; i++) {
+ for (i = -256<<LUT_BITS; i < 256<<LUT_BITS; i++) {
double f = ((i<<(9-LUT_BITS)) + (1<<(8-LUT_BITS)) - 1) / 512.0; // midpoint of the bin
- simil = 1.0 - FFABS(f) / 255.0;
+ simil = FFMAX(0, 1.0 - FFABS(f) / 255.0);
C = pow(simil, gamma) * 256.0 * f;
ct[(256<<LUT_BITS)+i] = lrint(C);
}