Question

I have a buffer with many positive 16bit values (which are stored as doubles) that I would like to quantize to 8bit (0-255 values).

According to Wikipedia the process would be:

• Normalize 16 bit values. I.e. find the largest and divide with this.
• Use the Q(x) formula with M=8.

So I wonder, if C have a function that can do this quantization, or does anyone know of a C implementation that I could use?

Lots of love,
Louise

Answer 1

Assuming the value d is in the interval [0.0, max]:

unsigned char quantize(double d, double max)
{
    return (unsigned char)((d / max) * 255.0);
}

I’m not sure what you mean by “16-bit values;” double precision values are 64-bit on any system using IEEE-754. However, if you have values of another numeric type, the process is effectively the same.