[x264-devel] rbsp_alignment_zero_bit

[Loren Merritt]

On Tue, 11 Nov 2008, Deepak Singh wrote:

> While using x264 code  I found that  "rbsp_alignment_zero_bit" at the end of
> the slice sometimes coming rbsp_alignemnt_zero_bit = 1, and sometimes
> rbsp_alignemnt_zero_bit = 0 while Only allowable value is 0.

Then you're misparsing where the slice ends. rbsp_alignment_zero_bit is 
not merely required to be 0, it's syntactically impossible to make it any 
other value. The last 1 and any 0s thereafter are the rbsp_trailing_bits, 
and all data before that is part of the payload.
The whole point of rbsp_trailing is so that you can know (to single-bit 
precision) where the payload ends. If there were another way to know which 
bit is the last bit, the standard wouldn't have included rbsp_trailing.

--Loren Merritt