As of last night the VP9 (profile 0)
bitstream is FINAL and the process of validating it on multiple platforms and
in different build environments and testing for submission into Chrome is under way.
The last few days
have been pretty hectic as we had to make several last minute changes. As
always seems to be the case, these were more complex than we had hoped and I
want to thank the whole team for working long hours to bring about closure. I also want to thank partners
and hardware vendors who have submitted comments and suggestions over the past
Details of the final issues
resolved over the last 7 days are as follows:-
Changes to the loop filter. Changes to make the
loop filter more HW friendly had to go through several iterations and gave rise
to a couple of late bugs. As is often the case, initial attempts to make it
more hardware friendly turned out to make things more difficult in SIMD
software implementations. Hopefully the final solution is a comfortable compromise
Changes to the way compound prediction modes are coded in
Though not conceptually complex and necessary to correctly constrain the
allowable compound prediction modes, this change touched a lot of files and
getting it done on time and debugged was a Herculean effort by those involved.
Definition and implementation of behaviour at the edge of
This relates to what prediction modes/sizes and transforms are allowed near the
edge of an image that does not break down nicely into 64x64 blocks. I mentioned
this at the summit and while it sounds simple, like all the simplest changes, it
was actually quite hard to get right. Again a big thank you to all involved in
working through the issues.
changes to the frame header (E.g.
coding of frame size not needed for all frames)
minor changes to the entropy coding of some symbols and some updates to the