values), so the comparison with vs_total_ac_bits is messed up on the
first couple loop iterations, leading to AC underflows.

the b->prev[] pointers were not being maintained correctly. We
potentially have to update b->prev[] both before and after the area
whose VLC length is getting adjusted.

this also might fix the ppc regression failure?

patch by (Dan Maas <dmaas maasdigital com>)


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@5064 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b