new options:
dwebp -alpha_dither
vwebp -noalphadither
When the source was marked as quantized, we use a threshold-averaging
filter to smooth the decoded alpha plane.
Note: this option forces the decoding of alpha data in one pass, and
might slow the decoding a bit.
The new field in WebPDecoderOptions struct is 'alpha_dithering_strength'
(0 by default, means: off). Max strength value is '100'.
Change-Id: I218e21af96360d4781587fede95f8ea4e2b7287a
User-hook can fail but error was not propagated back.
Change-Id: Ic79f9543bf767634a127eccfef90af855ff15c34
Also: some ad-hoc clean-up and API dusting. More to come later...
this change has the side-effect of using directory names in the
include, silencing a lint warning.
Change-Id: Ib91cf63a90534e32fadfa5c2372bfdb29f854d02
Needed to add 'volatile' and some casts.
Relevant excerpt from the 'man longjmp':
===============
The values of automatic variables are unspecified after a call to longjmp() if they meet all the following criteria:
· they are local to the function that made the corresponding setjmp(3) call;
· their values are changed between the calls to setjmp(3) and longjmp(); and
· they are not declared as volatile.
===============
Change-Id: Ic72dc92669513a820369ca52a038afa9ec88091f
on ExUtilLoadWebP() failure no allocated memory will be returned, so
it's safe to exit immediately. additionally, any webp specific problems
will already have been reported as part of the call to
WebPGetFeatures().
broken since:
4a0e739 dwebp: move webp decoding to example_util
Change-Id: Ibc632015a1f52bae7f96d063252624123fa7c2da
doing so is not part of ISO C; removes some pedantic warnings.
use webp/decode.h to pickup VP8StatusCode instead.
Change-Id: I19b35e0f8a36fb7c45944ae9ca86838e08b90548
there's still some malloc/free in the external example
This is an encoder API change because of the introduction
of WebPMemoryWriterClear() for symmetry reasons.
The MemoryWriter object should probably go in examples/ instead
of being in the main lib, though.
mux_types.h stil contain some inlined free()/malloc() that are
harder to remove (we need to put them in the libwebputils lib
and make sure link is ok). Left as a TODO for now.
Also: WebPDecodeRGB*() function are still returning a pointer
that needs to be free()'d. We should call WebPSafeFree() on
these, but it means exposing the whole mechanism. TODO(later).
Change-Id: Iad2c9060f7fa6040e3ba489c8b07f4caadfab77b
* allow reading from stdin for dwebp / vwebp
* allow writing to stdout for gif2webp
by introducing a new function ExUtilReadFromStdin()
Example use: cat in.webp | dwebp -o - -- - > out.png
Note that the '-- -' option must appear *last*
(as per general fashion for '--' option parsing)
Change-Id: I8df0f3a246cc325925d6b6f668ba060f7dd81d68
These are presets for lossless coding, similar to zlib.
The shortcut for lossless coding is now, e.g.:
cwebp -z 5 in.png -o out_lossless.webp
There are 10 possible values for -z parameter:
0 (fastest, lowest compression)
to 9 (slowest, best compression)
A reasonable tradeoff is -z 6, e.g.
-z 9 can be quite slow, so use with care.
This -z option is just a shortcut for some pre-defined
'-lossless -m xx -q yy' combinations.
Change-Id: I6ae716456456aea065469c916c2d5ca4d6c6cf04
New API options: WebPDecoderOptions.flip and 'dwebp -flip ...'
it uses negative stride trick.
Also changed the decoder code to support user-supplied
buffers with negative stride, independently of the
WebPDecoderOptions.flip value.
Change-Id: I4dc0d06f0c87e51a3f3428be4fee2d6b5ad76053
- 12/19/13: version 0.4.0
* improved gif2webp tool
* numerous fixes, compression improvement and speed-up
* dither option added to decoder (dwebp -dither 50 ...)
* improved multi-threaded modes (-mt option)
* improved filtering strength determination
* New function: WebPMuxGetCanvasSize
* BMP and TIFF format output added to 'dwebp'
* Significant memory reduction for decoding lossy images with alpha.
* Intertwined decoding of RGB and alpha for a shorter
time-to-first-decoded-pixel.
* WebPIterator has a new member 'has_alpha' denoting whether the frame
contains transparency.
* Container spec amended with new 'blending method' for animation.
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Merge tag 'v0.4.0'
libwebp 0.4.0
- 12/19/13: version 0.4.0
* improved gif2webp tool
* numerous fixes, compression improvement and speed-up
* dither option added to decoder (dwebp -dither 50 ...)
* improved multi-threaded modes (-mt option)
* improved filtering strength determination
* New function: WebPMuxGetCanvasSize
* BMP and TIFF format output added to 'dwebp'
* Significant memory reduction for decoding lossy images with alpha.
* Intertwined decoding of RGB and alpha for a shorter
time-to-first-decoded-pixel.
* WebPIterator has a new member 'has_alpha' denoting whether the frame
contains transparency.
* Container spec amended with new 'blending method' for animation.
* tag 'v0.4.0':
update ChangeLog
update NEWS description with new general features
gif2webp: don't use C99 %zu
cwebp: fix metadata output w/lossy+alpha
makefile.unix: clean up libgif2webp_util.a
update Changelog
bump version to 0.4.0
update AUTHORS & .mailmap
update NEWS for 0.4.0
Change-Id: I6df1b512fe0b697192f1f9b29431cd59aa6063d1
this would require a PRIuS or similar macro for proper platform
compatibility (Visual Studio for instance would be variants of %lu)
Change-Id: I2b9fcb1639db024775fb47dbcf79a2240f3d98f2
this enables webpmux to accept input files starting with '-' when using
-get/-set/-strip; -info & -frame expect an input file as one of their
parameters so no changes are necessary there.
Change-Id: I154eb6dc388258a7fb743ec76ba869bf9589be1b
This is to discourage generation of animated WebP images with ICC
profile, as
the real-world use-case for such images is rare at best.
Output of ICC/XMP metadata is now controlled by the '-metadata' option.
Change-Id: I8e3e29878c32bf46cbc661f50661bac602603c43
original/compressed pictures were not converted to an adequate YUVA
colorspace before computing the distortion.
Change-Id: I37775e9b7dbd6eca16c38e235e1df325858d36a1
Even at high quality setting, the U/V quantizer step is limited
to 4 which can lead to banding on gradient.
This option allows to selectively apply some randomness to
potentially flattened-out U/V blocks and attenuate the banding.
This option is off by default in 'dwebp', but set to -dither 50
by default in 'vwebp'.
Note: depending on the number of blocks selectively dithered,
we can have up to a 10% slow-down in decoding speed it seems.
Change-Id: Icc2446007f33ddacb60b3a80a9e63f2d5ad162de
When '-mixed' option is given, each frame would be heuristically chosen
to be
encoded using lossy or lossless compression.
The heuristic is based on the number of colors in the image:
- If num_colors <= 31, pick lossless compression
- If num_colors >= 194, pick lossy compression
- Otherwise, try both and pick the one that compresses better.
Change-Id: I908c73493ddc38e8db35b7b1959300569e6d3a97
This is to conform to man/gif2webp.1
Earlier, one needed to give both '-kmin 0' and '-kmax 0' for this to
work.
Also, suppress further warnings for kmin = 0 and/or kmax = 0 case.
Change-Id: I6f5eeb609aeffc159d0252a40a5734162f7e4e7d
Specifically:
- Merge OptimizeAndEncodeFrame with WebPFrameCacheAddFrame: they use the same
if-else structure.
- Move maintenance of 'prev_canvas' and 'curr_canvas' to util.
- Move ReduceTransparency() and FlattenPixels() calls to SetFrame(): This is in
preparation for the next patch: which will try try lossless encoding for
each frame, even when '-lossy' option is given.
- Make most methods static inside util.
No changes to output expected.
Change-Id: I1f65af25246665508cb20f0f6e338f9aaba9367b
quite rarely, it gives a different output
then without the HINT, but that's often for
a smaller size (tested with default -m and -m 6)
Change-Id: I51d221ab61f8e007983325031345728e8d80b241
helps during lossless compression.
10% average saving, but that's mostly on what was previously
'difficult' cases, where the gain is ~30-50% actually.
Non-difficult cases are mostly unchanged.
Tested over ~7k random web gifs.
Change-Id: I09db4560e4ab09105d1cad28e6dbf83842eda8e9
We reduce transparency by turning some transparent pixels into
corresponding RGB values from previous canvas.
This improves compression by about 23%.
Change-Id: I02d70a43a1d0906ac09a7e2dc510be3b2d38f593
useful for testing. Not listed in the man or README, since
it's only useful for testing the incremental decoding
(e.g. measuring the timing difference compared to non-incremental)
Change-Id: I8df8046e031d21006242babb5bcac09f8ff9f710
...and make gif2webp and vwebp compile without them.
Makefile.vc still to be updated...
Meanwhile the CL environment variable can be supplemented with
set CL=/DWEBP_HAVE_GL /IC:\opt\freeglut\include
Change-Id: I37a60b8c32aafd125bffa98b6cc9f57c022ebbd0
We use the 'do not blend' option for creating independent frames.
We also mark the already independent frames as 'do not blend'.
This bounds the maximum number of frames that need to be decoded to
decode a given frame, thus leading to a much better decoding performance.
Change-Id: I7cef98af2b53751ec36993fd2bd54f7f4c4aad2b
Doesn't work with WIC
+ redirect some info messages from stdout to stderr
+ fix the error reporting upon output-writing error
Change-Id: I92b8bd7a15e656a3f3cdfbf56299f024e39453f8
Earlier, all lossless images were assumed to contain alpha.
Now, we use the 'alpha_is_used' bit from the VP8L bitstream to determine
the
same.
Detecting an absence of alpha can sometimes lead to much more efficient
rendering, especially for animated images.
Related: refine mux code to read width/height/has_alpha information only
once
per frame/fragment. This avoid frequent calls to VP8(L)GetInfo().
Change-Id: I4e0eef4db7d94425396c7dff6ca5599d5bca8297
This is to ensure that the output WebP image is consistent with original
GIF when displayed against any background color.
Change-Id: I14218848153eb40358aa4ce331b2543d2fc2e86c
from x86_64-w64-mingw32-gcc
examples/wicdec.c: In function ‘ExtractICCP’:
examples/wicdec.c:131:21: warning: format ‘%u’ expects argument of type
‘unsigned int’, but argument 4 has type ‘size_t’ [-Wformat]
Change-Id: I6642dae62265a2276ae9ac96dd8ce6f1e2d37ca5
rather than symlink the webm/vpx terms, use the same header as libvpx to
reference in-tree files
based on the discussion in:
https://codereview.chromium.org/12771026/
Change-Id: Ia3067ecddefaa7ee01550136e00f7b3f086d4af4
