Commit Graph

73 Commits

Author SHA1 Message Date
James Zern
dfd32e4592 webp-container-spec: remove redundant sentence
in the note regarding metadata the possibility of multiple XMP/EXIF
chunks was already covered in the previous sentences.

based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_lars-eggert

Bug: webp:448
Change-Id: I6ee938e4d95bda1b144d3175fbf9f9296cf23352
2022-10-13 19:34:54 -07:00
James Zern
8a6185dd27 doc/webp-*: fix some punctuation, grammar
based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_lars-eggert

Bug: webp:448
Change-Id: I0a410b28b7b62fb4552ea3db444743be61469fe8
2022-10-13 19:34:54 -07:00
James Zern
3ed2b27517 webp-container-spec: clarify background color note
replace ...a transparency value (alpha)... with clearer text

based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_lars-eggert

Bug: webp:448
Change-Id: I79157b669c4317ebfc4f8434ee38f2666d1559ec
2022-10-11 15:05:33 -07:00
James Zern
951c292d12 webp-container-spec: come too late -> out of order
based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_lars-eggert

Bug: webp:448
Change-Id: Ie32d5500f3966b3c9f910675fb11d8a2cc60de3c
2022-10-11 15:05:33 -07:00
James Zern
902dd78762 webp-container-spec: prefer hex literals
to ABNF-style values; this makes the doc more consistent with
doc/webp-lossless-bitstream-spec.txt.

based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_lars-eggert

Bug: webp:448
Change-Id: I751cf0b7f728866ae663beb06e6352e5b3d848b2
2022-10-11 15:05:33 -07:00
James Zern
a8f6b5ee94 webp-container-spec: change SHOULD to MUST w/ANIM chunk
based on comments in:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_paul-wouters

Bug: webp:448
Change-Id: I9464dbbd734f1b78b287139eff13b1db8814c8d9
2022-10-11 15:05:33 -07:00
James Zern
1dc594352f webp-container-spec: add unknown fields MUST be ignored
based on comments in:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_paul-wouters

Bug: webp:448
Change-Id: I1eccb573b536f931b123261662efad7f92700500
2022-10-11 15:05:33 -07:00
James Zern
280a810f2a webp-container-spec: make padding byte=0 a MUST
this is consistent with the RIFF specification.

based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_robert-wilton

Bug: webp:448
Change-Id: I7a09177c9ea001b2e8759dcc5102242864c78105
2022-10-11 15:05:33 -07:00
James Zern
41f0bf680b webp-container-spec: update note on trailing data
clarify that the data is after the size specified by the file size in
the header; an alternate way to read the previous statement was that the
data was after the 'WEBP' fourcc.

based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_robert-wilton

Bug: webp:448
Change-Id: I7c5c5440a94cb817da51fe07d1ccf45d6af0f001
2022-10-11 15:05:33 -07:00
James Zern
6bdd36dbe7 webp-container-spec: clarify Chunk Size is in bytes
based on comments from:
https://datatracker.ietf.org/doc/draft-zern-webp/ballot/#draft-zern-webp_robert-wilton

Bug: webp:448
Change-Id: Idc874e5fa04d3cd122d31b87e833bf9f30ec9d05
2022-10-11 15:05:33 -07:00
James Zern
fcbc2d78ab Merge "doc/*.txt: restrict code to 69 columns" into main 2022-08-05 22:03:51 +00:00
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
c040a615b1 webp-container-spec.txt: normalize fourcc spelling
fourcc -> FourCC as it's defined in the terminology

Change-Id: I49e3a5aaba525b295701d8aac7b1700c4003ca77
2022-08-04 11:47:22 -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
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
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
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
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
6523e2d41d WebP Container:
annotate specific sections as experimental

Change-Id: If43222cef1c4fc2a8164b5f6ca4e89033379757d
2012-11-15 11:01:41 -08:00
Urvang Joshi
a7305c2ef0 Clarification for unknown chunks
clarify that writers *may* modify unknown chunks if they specifically
intend to do so.

Change-Id: I8348df2ec84648201ea781c7bfffd1f36eb3c8e5
2012-11-13 10:41:13 -08:00
Urvang Joshi
4c4398e2d5 Refine WebP Container Spec wrt unknown chunks.
Change-Id: Ibe950ab7afb2a7349f61c6fb81d587fba9ff27b6
2012-11-12 14:32:44 -08:00
Urvang Joshi
52ad1979d2 Animation specification in container spec
Change-Id: I3cb1d994a460d9a712998ca1045bf6bc7d953c04
2012-11-05 13:29:23 -08:00
Urvang Joshi
001b930219 Image fragment specification in container spec
Change-Id: If8cad296738465df4327dfb6b44efa7e0356070e
2012-11-02 15:37:49 -07:00
Urvang Joshi
391f9db9fa Ordering of description of bits in container spec
The description of bits in a byte should be from MSB to LSB

Change-Id: I50f2dfbb79b33eb434a771cca252c5d0f81fc71e
2012-11-02 15:27:37 -07:00
Urvang Joshi
d57357762a Metadata specification in container spec
Change-Id: I4b76697efb160145ffef3fd9df9905544c4e8792
2012-11-02 15:14:47 -07:00
Urvang Joshi
af6f0db291 Color profile specification in container spec
Change-Id: I53f849c7d93e1cdc971dda1fffd8f359f40607d3
2012-11-01 11:16:29 -07:00