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

[Michael Niedermayer]

Hi

On Thursday 03 October 2002 00:44, peter ross wrote:
[...]
> >* divx5 does not to detect the b-vop start code. maybe theres some
> >   magic bits between the p-vop and b-vop; maybe it has to be 8-bit
> >   padded, OR not padded?
>
> what iam saying is "there are some bits between the last p-vop
> coefficient AND the b-vop startcode". these bits are written,
> so that the start_code is byte aligned.
> e.g.
>        BitstreamPad(bs)
>        BitstreamWriteVopHeader(bs,...)
>
> xvid sets the padding bits to zero, whilst in "most" circumstances
> divx5 sets them to all to 1.
>
> maybe this is the problem? but i somehow doubt it.
it could be
the correct padding for mpeg4 is:
add 1 0 bit
then add n 1 bits to align to the next 8-bit boundary
see 5.2.4 of the standart

[...]

Michael