2014-03-24, 17:00
(2014-03-24, 14:56)fritsch Wrote: Once scaled from full to limited, it's non reversible.
Yes - but from Limited to Full it is (ignoring <16 BTB and >235 WTW clipping) isn't it? That was my point re: banding.
So if you have a Limited source file, scale to Full (introducing banding), and then scale back to Limited, that can remove the banding can't it?
Doesn't every Limited value scale to a unique Full value (with some Full values not being filled, creating the banding jumps?) thus allowing a lossless return to Limited (ignoring BTB and WTW) Won't this remove any banding that has been introduced by the Limited->Full scaling on the return Full->Limited scale. Isn't there a 1:1 mapping from Limited -> Full (which is thus reversible?)
Obviously if you start with a native Full signal, then you will lose information, but if your Full signal is itself derived from a Limited signal, won't that have no content in the areas where the information will be lost from?
I guess I'm imagining two 256 (or 1024 for 10 bit) value LUTS as that would be how I would have done it back in my hardware days! (256 bytes of ROM LUT - with the input video used to address the memory and the output video being the content of that memory location.)