[x264-devel] Re: MPEG4 question

[Michael Niedermayer]

Hi

On Mon, May 08, 2006 at 02:18:22PM +0200, Mathieu Monnier wrote:
[...]
> >Does old MPEG4 (not part 10) support changing the qscale in MB level 
> >(i.e.-changing it inside the frame).
> 
> Yes, but in a (very) restrictive way : the quantizer scale can only vary 
> from [-2:+2] of the quantizer scale of the last encoded macroblock. AVC 

only for I & P frames, B frames allow only {-2,0,+2} so you have to decide
between even and odd quantizers, furthermore you cannot change the quantizer
in macroblocks which have 4 motion vectors, h263 is similarely limited

h263+ lifts these (idiotic) limits and like mpeg1,mpeg2 and h264 allows the
whole range on every MB

[...]

-- 
Michael

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is

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