Commit Graph

107 Commits

Author SHA1 Message Date
James Zern
7a0a9935ed 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

Change-Id: Iaf4e8b71be27ef00fccd1d82b79bf96c01040f10
2022-08-04 19:35:24 -07:00
James Zern
8a4576ce26 webp-container-spec.txt: replace & with &
this conversion is handled by markdown processors

Change-Id: Ic679e40fcea577784deb8b455911bf1f201f2011
2022-08-03 11:12:23 -07:00
James Zern
db87088162 Merge "webp-container-spec.txt: make reserved 0 values a MUST" into main 2022-08-03 18:07:16 +00:00
James Zern
01d7d378d1 webp-lossless-bitstream-spec: number all sections
this makes the structure more consistent

Change-Id: Ie6c8b42506be73e565cfc4d39108eb4d8c038003
2022-08-02 19:03:51 -07:00
James Zern
337cf69f58 webp-lossless-bitstream-spec: mv Nomenclature after Intro
Change-Id: I3337513e48a8e604b154d91993bd7ff84d6c55ad
2022-08-02 18:50:59 -07:00
James Zern
5b87983ad0 webp-container-spec.txt: make reserved 0 values a MUST
these were intended as an extension point, but in this version of the
spec they're not defined. if they ever were used leaving them as SHOULD
could result in a source of incompatibility.

Change-Id: I1376ab7abe7d955ae335106f2faebc217dac77cd
2022-08-02 15:14:11 -07:00
James Zern
1a64a7e649 webp-container-spec.txt: clarify some SHOULDs
for compatibility SHOULDs are left as is with some additional
description given of behavior if the recommendation is ignored.

Change-Id: I7a25b1a6fd9f9594390c30fce3af5ca17c3158c0
2022-08-02 13:12:27 -07:00
James Zern
bec2c88a11 webp-container-spec.txt: move ChunkHeader to terminology
this avoids presenting it in the description of a chunk where it could
appear it was defining an element of the diagram

Change-Id: I51b2c2a0dcecb4fc130711ad37c884a434920ecd
2022-08-02 12:46:53 -07:00
James Zern
c9359332a3 webp-container-spec.txt: clarify 'VP8 '/'XMP ' fourccs
Note the fourth character is an ASCII space to avoid confusion.
Also update the FourCC definition to mention that they're case
sensitive.

Change-Id: I87d0cbcf06e7c25bf2b33419b4c8c891adb82a8a
2022-08-01 18:51:35 -07:00
James Zern
70fe3063a5 webp-container-spec.txt: rightsize table entries
Use the correct number of lines for fixed width entries like
ChunkHeader(). ':' is used instead of '|' for variable length entries.

Bug: webp:546
Change-Id: I6ec60af674c0777d5ea6ae99c8aa3c7854ddd9f9
Fixed: webp:546
2022-08-01 18:49:43 -07:00
James Zern
ddbf3f3f2a webp-container-spec.txt: update 'key words' text
RFC 2119 was updated by RFC 8174; use the text from there

+ change INFORMATIVE to informative to avoid confusion with the key
  words in the RFCs

Change-Id: I0a3fe9dc48d284e7ac95633896ffb855ecd1a229
2022-08-01 18:42:21 -07:00
Vincent Rabaud
e91451b69b Fix the lossless specs a bit more.
Bug: webp:551

Change-Id: I03f729f69d660f17e27cc601e91c703b241f1b83
2022-07-25 22:36:51 +02:00
James Zern
d01c1eb309 webp-lossless-bitstream-spec,cosmetics: normalize capitalization
in section headings

Change-Id: I43b2208f5e0efa32029d519ac9805e871eb51ed3
2022-07-20 10:36:23 -07:00
Jyrki Alakuijala
404c1622f8 Rename Huffman coding to prefix coding in the bitstream spec
... 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
2022-06-16 10:56:03 -07:00
James Zern
e74f8a62b2 webp-lossless-bitstream-spec,cosmetics: normalize range syntax
[N, M] -> [N..M] the latter is more common in this doc

Bug: webp:551
Change-Id: I2d317c4b8bb31d313123e981f93cd1feb346a98a
2022-05-14 20:51:43 -07:00
James Zern
5a709ec0d7 webp-lossless-bitstream-spec,cosmetics: fix code typo
code_lengths -> code_length_code_lengths
after:
86f94ee0 Update lossless spec with Huffman codes.

Bug: webp:551
Change-Id: I9e77f6db0fca6fe8294cb31a3015e723050094b5
2022-05-14 20:51:34 -07:00
James Zern
a2093acc4b webp-lossless-bitstream-spec: add amendment note
for recent changes to color transform, simple code length code, image
structure and details of decoding prefix codes

Bug: webp:551
Change-Id: I36a4d1ee3e25b8a56f5d926f4770374ace99bc2f
2022-05-13 18:50:55 -07:00
James Zern
86c669303a webp-lossless-bitstream-spec: fix BNF
color cache info precedes the meta huffman info

Bug: webp:551
Change-Id: Ibb69b4ffad6bff5693015be3fe6c600c53fd06c0
2022-05-13 18:41:30 -07:00
James Zern
232f22da5a webp-lossless-bitstream-spec: fix 'simple code' snippet
based on https://crbug.com/webp/551#c3 & https://crbug.com/webp/551#c4

Bug: webp:551
Change-Id: I4bcc19643b0bdda999247e9c3457d6954a49e35f
2022-05-13 18:41:20 -07:00
James Zern
44dd765def webp-lossless-bitstream-spec: fix ColorTransform impl
and the corresponding InverseTransform(); the operations were swapped.
The forward transform subtracts the deltas, the inverse adds them.

Bug: webp:551
Change-Id: Ieb90a24f843cee7cdfe46cbb15ec7d716ca9d269
2022-05-13 18:33:16 -07:00
James Zern
7a7e33e977 webp-lossless-bitstream-spec: fix TR-pixel right border note
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
2022-05-13 16:48:23 -07:00
vrabaud@google.com
86f94ee010 Update lossless spec with Huffman codes.
Bug: webp:551
Change-Id: I28b57c8e87a8023b727fe8359c2e2809cf92752d
2022-05-13 16:42:00 -07:00
James Zern
34bb332ca1 man/cwebp.1: add note about crop/resize order
+ normalize help text in [cd]webp

Bug: webp:561
Change-Id: Id92ec4228d4933cd033b2bf68a43192532cef483
2022-03-17 16:08:34 -07:00
James Zern
f0e9351cce webp-lossless-bitstream-spec,cosmetics: fix some typos
Bug: webp:551
Change-Id: I9ff90601b77deb9034ed7bef9cfd421d1f6e2e2b
2022-03-15 17:57:31 -07:00
James Zern
a30f219016 examples/webpmux.c: fix a couple of typos
in the code and help output; the man page is already correct

Change-Id: Id07d32cde24447cf61e1a2b3d55ab4a33549adde
2022-02-17 17:10:08 -08:00
Maryla
54e61a3864 Markdownify libwebp docs and reorganize them.
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
2022-02-15 15:31:56 +00:00
James Zern
88b6a396f1 webp-container-spec.txt,cosmetics: normalize formatting
- prefer Exif to EXIF when not referring to the chunk
- normalize use of code format for canvas / frame width & height

Change-Id: I7fc9e87baeb5d8e719274680ce621dcb078a985f
2022-01-25 18:36:36 -08:00
James Zern
b6f756e82b update http links
- 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
2021-11-23 10:13:40 -08:00
James Zern
8f5cb4c18e update rfc links
to https://datatracker.ietf.org/doc/html/... the http tools.ietf.org
links redirect here sometimes, in other cases they 404.

Bug: webp:544
Change-Id: I900972070d6c5659c45a86a89e78b870f42fe5bc
2021-11-17 11:03:35 -08:00
James Zern
21d24b4c08 webp-container-spec.txt: remove 'experimental' markers
unknown chunks as a group are well defined in the text

+ remove the Note about stable features as it matched the list given;
there are no WIP features for the format

Change-Id: I11a4de39f9d203b815879f0e9dea9c45b2ae6ff6
2021-10-22 12:17:59 -07:00
James Zern
1f5791398c cosmetics: remove use of 'sanity' / 'master'
replace with more inclusive terms or remove the comment entirely if the
meaning was already clear.

Bug: webp:507
Change-Id: Ica3bbf751ebf79f6668df6e6209af770248ff4ca
2021-05-21 10:38:40 -07:00
James Zern
71c39a06c8 webp-container-spec: correct frame duration=0 note
the interpretation of a 0 duration depends on the implementation;
merging of multiple frames isn't guaranteed, some may enforce a minimum
duration.

BUG=webp:380

Change-Id: Idf592049d2092e4cc5cfb2e4c59ddbc91bd52f9c
2018-04-20 15:23:12 -07:00
Pascal Massimino
13ae011e4c doc: use two's complement explicitly for uint8->int8 conversion
BUG=webp:225

Change-Id: I6bad131e275dbd992484e95a1b834010121281b8
2016-09-05 10:57:56 -07:00
Urvang Joshi
585d93dbba Container spec: clarify ordering of ALPH chunk.
Reported by user: https://code.google.com/p/webp/issues/detail?id=255

Change-Id: I9c027ea828d5a367b317744fad7607a16ed52fa5
2015-07-22 11:55:49 -07:00
James Zern
f0486968ba doc/webp-container-spec: update repo browser link
gerrit.chromium.org is deprecated, use chromium.googlesource.com.

Change-Id: Iaa6d6d18798dbd8cce908988287387f5cb8e8e64
2015-04-29 23:31:34 -07:00
James Zern
b510fbfe3b doc/webp-container-spec: note MSB order for chunk diagrams
addresses question in issue #241

Change-Id: Iff6a172d5822f6ec8b9bc0951a1c9cd3f98c9251
2015-02-12 20:18:58 -08:00
James Zern
e7d3df2314 doc/webp-container-spec: cosmetics
partially normalize indent, vertical whitespace and capitalization with
the copy used on developers.google.com/speed/webp

Change-Id: I8044418eeb9eaf5bd5c799675c74f6f845d503d6
2015-02-06 15:18:32 -08:00
James Zern
560394798f webp-container-spec: clarify background clear on loop
at the beginning of the loop there's an implicit clear of the entire
canvas to the background (or application defined) color. this avoids
adding the final composited frame to the first.

Change-Id: Ia3a52cf4482c6176334a5c9c99a0ddd07d1776e7
2015-02-04 18:07:00 -08:00
James Zern
a66e66c79d webp-container-spec: remove references to fragments
this portion of the format was never finalized

Change-Id: I80aa1b27457a0e52b047c7284df2f58b181ca5d8
2014-12-22 11:51:29 -05:00
Pascal Massimino
d7167ff7ce Amend the lossless spec according to issue #205, #206 and #224
http://code.google.com/p/webp/issues/detail?id=205 <- Select()
http://code.google.com/p/webp/issues/detail?id=206 <- out-of-bound colormap index
http://code.google.com/p/webp/issues/detail?id=224 <- version number MUST be 0

Change-Id: I56a575529862dfc8ad189ddcfc47ef59a58f273d
2014-09-18 08:21:02 +02:00
Urvang Joshi
d5bad03328 Animated WebP: add "do no blend" option to spec
Marking certain frames as "do not blend" helps avoiding alpha-blending
at decode/render time.

It also helps inserting I-frames (frames which can be independently
decoded) into the animation.

Change-Id: Iaa222805db88d2f1c81104ce9d882e7c7ff8cfdb
2013-08-14 11:50:15 -07:00
Lou Quillio
c606182edd webp-container-spec: Tighten language added by last
Change-Id: Id7719ba7f1ddfd7b54a1985771b2811318a7c0d7
2013-07-09 18:45:39 -07:00
Urvang Joshi
5e9675329c Container spec: a clarification on background color.
Change-Id: Ifeb565bd162abfa03dfcbf8b576657fe83956a6c
2013-06-20 17:38:08 -07:00
Urvang Joshi
403bfe820c Container spec: Clarify frame disposal
- Add a note that disposal only applies to the frame rectangle
- Add the formula for alpha-blending.
- Note that alpha-blending would occur for the common rectangle
- Also note the case when both color profile and disposal are
present.

Change-Id: I214787dd64453edf3b0cdaff3951015281a32ee4
2013-03-29 11:42:17 -07:00
James Zern
3e7a13a008 Merge "Container spec: clarify the background color field" into 0.3.0 2013-03-26 17:38:07 -07:00
James Zern
14af77452b container doc: add a note about the 'ANMF' payload
this consists of padded chunks, so ANMF should require none

Change-Id: I5dff623b56d8a466dc9be03ee87d1d2d19efc088
2013-03-26 17:25:27 -07:00
Urvang Joshi
cc635efa01 Container spec: clarify the background color field
Change-Id: I03f634cbd147c2851eb06ddbc7b1014e04e21038
2013-03-26 17:22:18 -07:00
James Zern
e3e339497e container doc: move RIFF description to own section
- remove some little used terms
- condense file header description
- add description of FourCC

Change-Id: Ia873652f41789811f3fb2ec97182a068ac727961
2013-03-26 17:16:12 -07:00
Urvang Joshi
d1e21b13b7 Remove 'status: experimental' from container spec
For features that are to be released in v0.3.0.

Change-Id: Ib8961f8cde0474aeaad5796bd0821db812edffcd
2013-03-13 18:16:30 -07:00
Urvang Joshi
8425aaee8f Formatting fixes in lossless bitstream spec
- 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
2013-01-18 14:35:47 -08:00