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Incorporate gdoc changes through 2012-06-08

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modified:   doc/webp-lossless-bitstream-spec.txt

Change-Id: I01c04772bff7e3d7d6f0b526949cd846b5a97c8d
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Lou Quillio 2012-06-14 12:03:55 -07:00
parent 7a18248716
commit 91011206ad
1 changed files with 11 additions and 10 deletions
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doc/webp-lossless-bitstream-spec.txt
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@ -9,10 +9,10 @@ end of this file.
--> -->
WebP Lossless Bitstream Specification Specification for WebP Lossless Bitstream
===================================== =========================================
_Working Draft, v0.2, 20120523_ _2012-06-08_
Abstract Abstract
@ -866,7 +866,9 @@ codes to the number of meta Huffman codes.
### Decoding of meta Huffman codes ### Decoding of meta Huffman codes
There are two ways to code the meta Huffman codes, indicated by one bit. There are two ways to code the meta Huffman codes, indicated by one bit
for the ARGB image and is an implicit zero, i.e., not present in the
stream for all predictor images and Huffman image itself.
If this bit is zero, there is only one meta Huffman code, using Huffman If this bit is zero, there is only one meta Huffman code, using Huffman
codes 0, 1, 2, 3 and 4 for green, alpha, red, blue and distance, codes 0, 1, 2, 3 and 4 for green, alpha, red, blue and distance,
@ -952,8 +954,7 @@ the number of pixels (xsize * ysize).
#### Structure of the image data #### Structure of the image data
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<entropy-coded image> ::= <optional meta huffman> <entropy-coded image> ::= <color cache info><optional meta huffman><huffman codes>
<color cache info><huffman codes>
<lz77-coded image> <lz77-coded image>
<optional meta huffman> ::= 1-bit value 0 | <optional meta huffman> ::= 1-bit value 0 |
(1-bit value 1; (1-bit value 1;
@ -974,8 +975,8 @@ the number of pixels (xsize * ysize).
A possible example sequence A possible example sequence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<RIFF header><image size>1-bit<subtract-green-tx> <RIFF header><image size>1-bit value 1<subtract-green-tx>
1-bit<predictor-tx>0-bit<huffman image> 1-bit value 1<predictor-tx>1-bit value 0<huffman image>
<meta huffman code><color cache info><huffman codes> <color cache info><meta huffman code><huffman codes>
<lz77-coded image> <lz77-coded image>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~