webp-lossless-bitstream-spec: split code length section

Make Simple / Normal Code Length Code their own section for ease of
reference.

Bug: webp:611
Change-Id: I1e6ed50d98f9258cacb163d2059716b5356e8b6f
This commit is contained in:
James Zern 2023-06-21 19:20:12 -07:00
parent 7a12afcc54
commit 08d60d6006

View File

@ -846,7 +846,7 @@ node using the _normal code length code_, all but one code length are zeros,
and the single leaf node value is marked with the length of 1 -- even when no
bits are consumed when that single leaf node tree is used.
**(i) Simple Code Length Code:**
##### Simple Code Length Code
This variant is used in the special case when only 1 or 2 prefix symbols are in
the range \[0..255\] with code length `1`. All other prefix code lengths are
@ -882,7 +882,7 @@ blue can be empty if all pixels within the same meta prefix code are produced
using the color cache. However, this case doesn't need special handling, as
empty prefix codes can be coded as those containing a single symbol `0`.
**(ii) Normal Code Length Code:**
##### Normal Code Length Code
The code lengths of the prefix code fit in 8 bits and are read as follows.
First, `num_code_lengths` specifies the number of code lengths.