Re: [fluid-dev] Purpose of dither?

[Miguel Lobo]

> Yes, you absolutely right. But look at that code again:
>
>   for (c = 0; c < DITHER_CHANNELS; c++) {
>     dp = 0;
>     for (i = 0; i < DITHER_SIZE-1; i++) {
>       d = rand() / (float)RAND_MAX - 0.5f;
>       rand_table[c][i] = d - dp;
>       dp = d;
>     }
>     rand_table[c][DITHER_SIZE-1] = 0 - dp;
>
> We subtract previous dither value from current to prevent noise
> modulation. I use dither table to get maximum speed.

I actually felt curious about the subtraction of the previous value too.  What 
do you mean by "noise modulation"?  (And yes, this time I have looked it up 
in Wikipedia ;)).

Regards,
Miguel