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
