webp-lossless-bitstream-spec: split Meta Prefix Codes section

Make Entropy Image and Interpretation of Meta Prefix Codes their own
section for ease of reference.

Bug: webp:611
Change-Id: I2dba7b4efd02d8bb250810ebff42ac1687262804
This commit is contained in:
James Zern 2023-06-22 17:28:02 -07:00
parent 7b634d8f0c
commit 7f1b6799db

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@ -963,7 +963,7 @@ value:
* If this bit is one, the image uses multiple meta prefix codes. These meta
prefix codes are stored as an _entropy image_ (described below).
**Entropy image:**
##### Entropy Image
The entropy image defines which prefix codes are used in different parts of the
image.
@ -982,7 +982,7 @@ where `DIV_ROUND_UP` is as defined [earlier](#predictor-transform).
The next bits contain an entropy image of width `prefix_xsize` and height
`prefix_ysize`.
**Interpretation of Meta Prefix Codes:**
##### Interpretation of Meta Prefix Codes
The number of prefix code groups in the ARGB image can be obtained by finding
the _largest meta prefix code_ from the entropy image: