[XviD-devel] divx5, bframes and non-coded vops

Michael Niedermayer xvid-devel@xvid.org
Wed, 2 Oct 2002 16:35:39 +0200


Hi

On Wednesday 02 October 2002 16:11, Christoph Lampert wrote:
> > > Or did I overlook anything?
> >
> > yes, this is for the arithmetic coder IIRC, which is used for wavelet
> > coded images in mpeg4 IIRC
>
> Good point! Thanks.
>
> So it's possible to write any 16 bit value into the bitstream without
> having to care about its value being some start-code? Thank god, it would
> have been _horrible_ otherwise...
yes, mpeg is designed that no startcode emulation can happen in any valid 
bitstream (the vlc codes are selected so that this cant happen)
for startcode emulation u need 23 0 bits followed by a 1 bit
for the 16bit time stuff example, there is allways a 1-bit directly before and 
directly afterwards (the marker bits, yes thats the purpose of these marker 
bits)

[...]

Michael