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Doc: container spec text tweaks

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Change-Id: I8e29f1c814b0c8f6aa268562d8653989caaf281d
modified:   doc/webp-container-spec.txt
This commit is contained in:
Lou Quillio 2012-07-18 12:16:51 -07:00
parent c2416c9b61
commit 4e2e0a8cac
1 changed files with 8 additions and 7 deletions
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doc/webp-container-spec.txt
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@ -171,7 +171,7 @@ This layout SHOULD be used if the image requires _lossy_ encoding and does not
require transparency or other advanced features provided by the extended format. require transparency or other advanced features provided by the extended format.
Files with this layout are smaller and supported by older software. Files with this layout are smaller and supported by older software.
Simple WebP (lossy) file header: Simple WebP (lossy) file format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
@ -211,7 +211,7 @@ This layout SHOULD be used if the image requires _lossless_ encoding (with an
optional transparency channel) and does not require advanced features provided optional transparency channel) and does not require advanced features provided
by the extended format. by the extended format.
Simple WebP (lossless) file header: Simple WebP (lossless) file format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
@ -393,10 +393,11 @@ Alpha bitstream: _Chunk Size_ - `1` bytes
: Encoded alpha bitstream. : Encoded alpha bitstream.
This optional chunk contains encoded alpha data for a single frame. This optional chunk contains encoded alpha data for the image. An image
An image containing a 'VP8L' chunk SHOULD NOT contain this chunk. containing a 'VP8L' chunk SHOULD NOT contain this chunk.
**Rationale**: the transparency information of an image is already part of
the 'VP8L' chunk. **Rationale**: The transparency information of the image is already part
of the 'VP8L' chunk.
The alpha channel data is stored as uncompressed raw data (when The alpha channel data is stored as uncompressed raw data (when
compression method is '0') or compressed using the lossless format compression method is '0') or compressed using the lossless format
@ -436,7 +437,7 @@ and [Simple file format (lossless)](#simple-file-format-lossless) respectively.
#### Unknown Chunks #### Unknown Chunks
A file MAY contain other unknown chunks. Readers SHOULD be ignore these chunks. A file MAY contain other unknown chunks. Readers SHOULD ignore these chunks.
Writers SHOULD preserve them in their original order. Writers SHOULD preserve them in their original order.
Example file layouts Example file layouts