for fixes to the distance_map pseudo-code, the inverse color transform
description and the num_code_lengths check.
Bug: webp:448
Bug: webp:551
Change-Id: Id7e791b97704dd64bb9519657ce48b92cb457ae4
The prose describing the process was missed in:
44dd765d webp-lossless-bitstream-spec: fix ColorTransform impl
Bug: webp:448
Bug: webp:551
Change-Id: If5fb95103ffedeed113e3ad62510f3a19bfd280e
in the 'Normal Code Length Code' description the number of valid code
lengths is 19, not 18.
Bug: webp:448
Bug: webp:551
Change-Id: Id929604e1d771cb09b2d0ac617e83f21077f21de
'zero alpha pixels' was a bit hard to parse; replace this with something
more explicit
Bug: webp:448
Change-Id: Ifc8c93af5520ffdafc58e3fc311dfb4cb19626e9
this is similar to an earlier change for most of the code examples:
7a0a9935 doc/*.txt: restrict code to 69 columns
some renderers may limit output to 72 and use a 3 space indent; this
avoids overflowing into the margin
Bug: webp:448
Change-Id: I2e8d66f598889c7bd824e911ea01fd70f98a4130
The distance code read from the bitstream is reduced by 1 before doing
the lookup. The prose describing the lookup was correct, the pseudocode
failed to subtract 1 and used x/y instead of xi/yi from the lookup.
Bug: webp:448
Change-Id: I152477b888c26a0473a35373d3d331fddd14237f
this has a better canonical reference [1] and is preferred in IETF docs
[1] https://www.rfc-editor.org/rfc/rfc5234
Bug: webp:448
Change-Id: I3f0bd34d3ca4c62b255d5d6cbae0c55e2940dfb5
some renderers may limit output to 72 and use a 3 space indent; this
avoids overflowing into the margin
Change-Id: Iaf4e8b71be27ef00fccd1d82b79bf96c01040f10
... since no guarantee of Huffman coding can be introduced at decoding
time and encoding didn't actually use Huffman coding in the first place
Bug: webp:551
Change-Id: I400466bb3b4a1d5506353eb3f287d658603164ee
for recent changes to color transform, simple code length code, image
structure and details of decoding prefix codes
Bug: webp:551
Change-Id: I36a4d1ee3e25b8a56f5d926f4770374ace99bc2f
and the corresponding InverseTransform(); the operations were swapped.
The forward transform subtracts the deltas, the inverse adds them.
Bug: webp:551
Change-Id: Ieb90a24f843cee7cdfe46cbb15ec7d716ca9d269
the value of the TR-pixel on the right border is the leftmost pixel on
the current row, not the previous one
Bug: webp:551
Change-Id: I157e8c16ce43a9f52c36aa880be1be3bef19c063
Break the main README into into multiple pages in the doc/ directory,
except for the tests, swig and webp_js docs which are in the corresponding
directories.
The webp mux doc is merged into the API doc and the tools doc.
Change-Id: Ia407617dd88094f4662841d37947cfef80799914
- prefer https
- metadataworkinggroup.org/com seem to be offline; the web archive link
was obtained from exiftool: https://exiftool.org/TagNames/MWG.html
- fix kramdown link, rubyforge has been gone a long time
- fix png/zlib links
Bug: webp:544
Bug: b/202302177
Change-Id: Id69de4553e7baf00393f12a2c1acb262443a1a93
- Escape brackets for which kramdown was generating a warning.
Note: This only changes this source file; output HTML would look exactly
the same.
- Also write '5' in words ('five').
Change-Id: I472a03c090a12eb7520719ea463469b36a2736b9
- Clarify the BNF using 'Huffman code groups' and 'Huffman code group'.
- Introduce same terminology in 'Interpretation of meta Huffman codes'.
- Make explicit mention of what is the number of Huffman code groups,
number of Huffman codes and the relation between the two.
Change-Id: I07aa9b62c1d464cd25dc02ac1a68d338b575bdc2
- Rectify a few BNF descriptions
- Corrections in "Decoding Flow of Image Data" section:
1. The sequence in case of "S < 256" should be green, red, blue, alpha.
2. In case of "S >= 256 + 24", the index should be "S - (256 + 24)".
- Provide more description to clarify "Decoding Flow of Image Data" section.
- Some cosmetics: use '1's instead of '1, 2, 3...' sequence, as kramdown takes
care of sequencing.
Change-Id: I2b76caf72f67aae813522dc1a4115f8ec8ea6db7
The color transform block size is stored as 3 bits, not 4.
Fixed the description. The code snippet is already correct.
Change-Id: I830d848b54c121cb5426ca06853a3f1184fd9a31
The prediction block size is stored as 3 bits, not 4.
Fixed the description. The code snippet is already correct.
Change-Id: Iaa66a7e9817b58a2557c9a71c2231cc400b6ae4d
Substantial edit, though less than 100% thorough. This
makes changes that are clearly safe, but avoids others
where my domain knowledge is incomplete and accuracy
might be compromised.
modified: doc/webp-lossless-bitstream-spec.txt
Change-Id: I89361a2e1157b8d2e44a8b4f4603f65833f0c1e6
