[XviD-devel] some question about xvid and mpeg4

Marco Al xvid-devel@xvid.org
Fri, 24 Jan 2003 16:32:25 +0100


Marco Al wrote:
> James Hauxwell wrote:
>
>> changing macrobloc quant in darker or "flatter" area won't reduce
>> filesize??
>>
>> Yes it will, as you produce more zero value coefficients, so the VLC
>> does a better job = fewer bits.
>
> But if you save less than 3 bits for a given MB you increase filesize of
> course, which isnt all that unlikely for motion compensated blocks.

I should add that sometimes you can still win out by spreading the bits needed
for the DQUANT over multiple MBs but it is impossible to know this will happen
without looking ahead.

Marco