[XviD-devel] 1.0 bug

[Radek Czyz]

Michael Militzer wrote:
> Hi,
> 
> is this problem with time codes and N_VOPs happening with our skip frame
> feature? Because there are also N_VOPs created in b-frame packed mode and
> these intentionally have wrong time codes as they simply duplicate the
> time code of the previous p-frame afaik (thanks to DXN...)

Yes yes, don't worry, it's in the "frame drop ratio" code.
When we're coding an n-vop, we make it our new reference (because it's
simpler this way) but copy all important data from real reference:
picture, quant, fcode, macroblocks etc. We can now update our reference
frame as if p-vop was coded, but it's still the same old frame, only
memory location is different.

The only thing we forgot to copy is timestamp. Because of that, in a
sequence P B N P the first b-frame appeared before its forward reference
(in terms of timestamps) so had negative time increment and crashed  -
(unsigned)-1 bits were written to the bitstream.

Radek