- 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
Similarly to "-set loop <>", this is useful to set
the parameter at global level and not just while assembling
the frames separately.
Change-Id: I79bcbe37f8ff50b9904e78d14011ccbac72f17a1
This is particularly useful for multi-pass search (but not only),
to prevent the search from going over or below a reasonable threshold.
E.g.: 'cwebp -qrange 50 80 ...' will prevent any unreasonable degradation.
new cwebp option: -qrange min max
Change-Id: I59f394533535fc20b6996bc0895f4301476d5eff
This is to make the initial window be rescaled in case the image
dimension is too large to fit the display.
BUG=webp:433
Change-Id: Ib04c12962bc8c26e74c8a6193829214da636ebde
Option -usebgcolor may be used to display ANIM background color (or white if no ANIM chunk), blended on top of checkerboard. By default this is disabled (old behavior) to easily see transparent areas. Spec says that "background color MAY be used", so it's an option.
Key b may be pressed to toggle ANIM background color display. There are visual artifacts (leftovers) when toggling during an animation. This is already the case for rescaling, toggling info etc. (fixing it implies storing viewport render or rendering whole animation from start till current frame).
BUG=webp:394
Change-Id: If9ab898b2eac77226f30f062d522f9861789ef8f
This is to harmonize the -h/-version options on all our examples.
+ added GetAnimatedImageVersions() method to anim_util.*
Change-Id: I2304a1c29e310682e97f236d3867274a192a7a09
if a single text file name is supplied as argument
(e.g.: 'webpmux my_long_list_of_frames.txt'), the command
line arguments are actually parsed from this file.
Tokenizer will remove space, tabs, LF, CR, returns, etc.
+ changed ImgIoUtilReadFile() to return a null-terminated
data, for convenience.
+ misc clean-up in the code
BUG=webp:355
Change-Id: I76796305641d660933de5881763d723006712fa9
---
This patch fixes the compatibility for loop-count handling.
This aims at addressing the change in Chrome handling of loop-count
prior to M63.
Before M63: loop-count interpretation was aligned to GIF's behaviour in
Chrome, but incompatible with WebP's spec. In particular, you couldn't
loop exactly once.
Post-M63: loop-count in WebP is really the total number of loops. Gif2webp
will convert correctly from a GIF source by adjusting the loop count.
Note: The Chrome version can be retrieved from the User-Agent
string (chrome://version).
An M63 version will contain the pattern:
Chrome/63.x.xxxx.xx
for instance.
Change-Id: Ie6dc13227e6498f4d7af2f09247913648997648a
Documentation says: "if kmin == 0, then key-frame insertion is disabled;
and if kmax == 0, then all frames will be key-frames."
Reading this, you'd expect that if kmax == 0, then with any kmin <= 0
all frames will be key-frames. But actually the kmin <= 0 test is caught
first and you get the opposite (no keyframes but the first). You'd have
instead to set kmax == 0 and any value kmin > 0, which is absolutely
counter-intuitive (reversing order).
Moreover kmax == 1 has no valid kmin (kmin == 1 conflicts with the
`kmax > kmin` rule and kmin == 0 conflicts with `kmin >= kmax / 2 + 1`).
So it should be considered an exception too.
Instead I propose this new logic:
- kmax == 1 means that all frames are keyframes (you are explicitly
requesting a keyframe every 1 frame at most, i.e. all frames).
- kmax == 0 means no keyframes (you ask for a keyframe every 0 frames,
i.e. never).
This is more "logical" language-wise, and also does not involve any
conflicts about what if both kmax and kmin are 0, since now a single
property value is meaningful for the 2 exceptional cases.
Change-Id: Ia90fb963bc26904ff078d2e4ef9f74b22b13a0fd
(cherry picked from commit 2dc0bdcaee)
the default is format is roman, fixes:
`R' is a string (producing the registered sign), not a macro.
Change-Id: If2bce714eff1237cd1702ae1143323249d85b93b
it actually disables the disposal / blending method
and just displays the raw delta values.
Useful for debugging.
TODO: Outline the refreshed area with a drawn rectangle?
Change-Id: I6f8cddd0aad8b953cff78a693ae7e8c31def010c
The options are now:
-duration d -> set the whole animation to duration 'd'
-duration d,s -> set only frame 's' to duration 'd'
-duration d,s,e -> set only interval [s,d] to duration 'd'
+ style fix
Change-Id: I72e95282d520146f76696666f44280ad9506affa
this will force a constant duration for an interval of frames
in an animation.
Notes:
a) '-duration [...]' can be repeated as many times as needed.
b) intervals are taken into account in option order. If they overlap, values will be overwritten.
c) 'start' and 'end' can be omitted, but not the duration value.
d) 'end' can be equal to '0', in which case it means 'last frame'
e) single-image files are untouched (ie. not turned into an animation file).
Some example usage:
webpmux -duration 150 in.webp -o out.webp
webpmux -duration 33,10,0 in.webp -o out.webp
webpmux -duration 200,2 -duration 150,0,50 in.webp -o out.webp
Change-Id: I9b595dafa77f9221bacd080be7858b1457f54636
This is to prevent users shooting in the foot using -psnr or
-size alone and not getting the expected result.
Change-Id: I67a3289e4ec0a2a813c98807f2ec5e600f52dc63
Rename the flag to exact instead of the opposite cleanup_alpha. Add the flag to
WebPConfig. Do the cleanup in the webp encoder library rather than the cwebp
binary, this will be needed for the next stage: smarter alpha cleanup for
better compression which cannot be done as a preprocessing due to depending on
predictor choices in the encoder.
Change-Id: I2fbf57f918a35f2da6186ef0b5d85e5fd0020eef
Updated the near-lossless level mapping and make it correlated to lossy
quality i.e 100 => minimum loss (in-fact no-loss) and the visual-quality loss
increases with decrease in near-lossless level (quality) till value 0.
The new mapping implies following (PSNR) loss-metric:
-near_lossless 100: No-loss (bit-stream same as -lossless).
-near_lossless 80: Very very high PSNR (around 54dB).
-near_lossless 60: Very high PSNR (around 48dB).
-near_lossless 40: High PSNR (around 42dB).
-near_lossless 20: Moderate PSNR (around 36dB).
-near_lossless 0: Low PSNR (around 30dB).
Change-Id: I930de4b18950faf2868c97d42e9e49ba0b642960
Enable the WebP near-lossless feature by pre-processing the image to smoothen
the pixels.
On a 1000 PNG image corpus, for which WebP lossless (default settings) gets
25% compression gains, following is the performance of near-lossless feature
at various '-near_lossless' levels:
-near_lossless 90: 30% (very very high PSNR 54-60dB)
-near_lossless 75: 38% (very high PSNR 48-54dB)
-near_lossless 50: 45% (high PSNR 42-48dB)
-near_lossless 25: 48% (moderate PSNR 36-42dB)
-near_lossless 10: 50% (PSNR 30-36dB)
WebP near-lossless is specifically useful for discrete-tone images like
line-art, icons etc.
Change-Id: I7d12a2c9362ccd076d09710ea05c85fa64664c38
