Before, the color cache size was chosen optimally for LZ77 and
the same value was used for RLE. Now, we optimize its value
taking both LZ77 and RLE into account.
Unfortunately, that comes with a small CPU hit.
Change-Id: I6261f04af78cf0784bb8e8fc4b4af5f566a0e071
Between each iteration we keep track of the previously found
potential merge hence less work to do.
Change-Id: I2b6237447e79443516a6111727d96c24f10bd98a
It was a bad implementation of a Lehmer random number generator
(the saturation was done wrong and mostly & was used instead of % .....).
That lead to "for" loop stuck with the same values given a specific seed,
hence wasted "for" loops (e.g. seed getting at 374988608 and modulo of 64
later leads to 0 even when updating the seed with the old formula).
As the "for" loops now always return a proper pair of histograms, their
number can greatly be reduced, hence a speedup.
Change-Id: I9f5b44d66cc96fd4824189d92276c3756c8ead5b
Previously, the stochastic method for histogram
combination could finish in a greedy way
if the number of iterations to perform so was smaller.
Except that another greedy combination was performed
afterwards ... hence wasted CPU in some cases.
Change-Id: Ic0f26873e6dc746679486b91cb35d73efee91931
The initial re-writing of this part of the code with intervals
had to be done with a complex logic (mostly intervals with a
lower and upper bound, not a constant value like now) to properly
deal with the inefficiencies of the then LZ77 algorithm.
The improvements made to LZ77 since, now allow for a simpler logic.
There were also small errors in the interval insertion logic
that lead to small inefficiencies (hence a slightly better
compression rate).
Change-Id: If079a0cafaae7be8e3f253485d9015a7177cf973
this avoids duplicates between these trees and dsp/, e.g., enc/tree.c,
dec/tree.c, making pulling the whole library source tree into one target
possible
BUG=webp:279
Change-Id: I060a614833c7c24ddd37bf641702ae6a5eef1775
The previous optimization was performing dichotomy on a function that
is anything in practice, hence a bit of randomness.
Also, two magic constants were used, one for an extra constant cost,
one for an extra linear cost. Both values/models were empirical.
A brute force search for the best cache size is now performed.
To have less CPU impact, a speed optimization is also made by not
inserting a value again and again.
This makes sense but it's also the most common case of when LZ77 is
useful hence an overall improvement sometimes.
Change-Id: I57de5750ad2313b2feecbcd15cd6e4feeb98e5c8
- 12/13/2016: version 0.5.2
This is a binary compatible release.
This release covers CVE-2016-8888 and CVE-2016-9085.
* further security related hardening in the tools; fixes to
gif2webp/AnimEncoder (issues #310, #314, #316, #322), cwebp/libwebp (issue
#312)
* full libwebp (encoder & decoder) iOS framework; libwebpdecoder
WebP.framework renamed to WebPDecoder.framework (issue #307)
* CMake support for Android Studio (2.2)
* miscellaneous build related fixes (issue #306, #313)
* miscellaneous documentation improvements (issue #225)
* minor lossy encoder fixes and improvements
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Merge tag 'v0.5.2'
libwebp-0.5.2
- 12/13/2016: version 0.5.2
This is a binary compatible release.
This release covers CVE-2016-8888 and CVE-2016-9085.
* further security related hardening in the tools; fixes to
gif2webp/AnimEncoder (issues #310, #314, #316, #322), cwebp/libwebp (issue
#312)
* full libwebp (encoder & decoder) iOS framework; libwebpdecoder
WebP.framework renamed to WebPDecoder.framework (issue #307)
* CMake support for Android Studio (2.2)
* miscellaneous build related fixes (issue #306, #313)
* miscellaneous documentation improvements (issue #225)
* minor lossy encoder fixes and improvements
* tag 'v0.5.2': (54 commits)
update ChangeLog
anim_util: quiet implicit conv warnings in 32-bit
jpegdec: correct ContextFill signature
Remove some errors when compiling the code as C++.
vwebp: clear canvas during resize w/o animation
tiffdec: restore libtiff 3.9.x compatibility
update NEWS
AnimEncoder: avoid freeing uninitialized memory pointer.
WebPAnimEncoder: If 'minimize_size' and 'allow_mixed' on, try lossy + lossless.
fix a potential overflow with MALLOC_LIMIT
bump version to 0.5.2
update AUTHORS & .mailmap
iosbuild.sh: add WebPDecoder.framework + encoder
AnimEncoder: Correctly skip a frame when sub-rectangle is empty.
Fix assertions in WebPRescalerExportRow()
fix a typo in WebPPictureYUVAToARGB's doc
systematically call WebPDemuxReleaseIterator() on dec->prev_iter_
doc: use two's complement explicitly for uint8->int8 conversion
Anim_encoder: correctly handle enc->prev_candidate_undecided_
WebPPictureDistortion(): free() -> WebPSafeFree()
...
Change-Id: I16bcf54af41ce8fad98d4fbc8aa1df58f338fc23
When try_both_modes=0 (that is: -m 0 or -m 1), and the mode is i4,
we were still sometimes falling back to (unexplored, uninitialized) i16 mode,
which resulted in a enc/dec mismatch.
This was mainly occurring for large images (when bit_limit is low enough)
We disable the fall-back by disabling bit_limit using a large MAX_COST threshold.
Change-Id: I0c60257595812bd813b239ff4c86703ddf63cbf8
(cherry picked from commit 0a3838ca77)
the min-distortion was quite too low. And we were also
considering the fully skipped macroblocks (nz=0) in the stats.
We need to have at least *some* non-zero dc coeffs (nz=0x100XXXX).
Fix also two typos in StoreMaxDelta: the v0/v1 comparison was wrong,
and the DCs[] coeffs are actually already in ZigZag order.
Change-Id: I602aaa74b36f7ce80017e506212c7d6fd9deba1f
(cherry picked from commit e4cd4daf74)
max_i4_header_bits_ could drop to zero for difficult image and trigger
a loop. Surprisingly, StatLoop() didn't have this bug.
Change-Id: Idc0f9eadef30a2b2f02041b994f25def30901e36
(cherry picked from commit 21e7537abe)
Pick the mode with the smallest alpha.
It only affects m0, in which case the mode decision is not re-examined
later in VP8Decimate(). Tests on some natural content png images show
PSNR increase as well as visual quality improvement.
Change-Id: Iea997e718cd7477160fa05eb7cfb35f4cec2fa9a
(cherry picked from commit 1377ac2ec1)
avoiding triplets of data should make it easier to write SSE2 versions.
FilterRow() can now filter all input in one single pass
-> conversion is 15-20% faster (but still overall slow compared to -pre 0)
Change-Id: I14c3215e672fdecde7ec80394e814bdc7445019f
When try_both_modes=0 (that is: -m 0 or -m 1), and the mode is i4,
we were still sometimes falling back to (unexplored, uninitialized) i16 mode,
which resulted in a enc/dec mismatch.
This was mainly occurring for large images (when bit_limit is low enough)
We disable the fall-back by disabling bit_limit using a large MAX_COST threshold.
Change-Id: I0c60257595812bd813b239ff4c86703ddf63cbf8
avoids int rollover when working with large input
BUG=webp:312
Change-Id: I6ad9f93b6c4b665c559bff87716a7b847f66a20d
(cherry picked from commit 342e15f0ce)
avoids int rollover when working with large input
BUG=webp:312
Change-Id: I2881bec2884b550c966108beeff1bf0d8ef9f76b
(cherry picked from commit 1147ab4ee7)
avoids int rollover when working with large input
BUG=webp:312
Change-Id: I693cbb295df9cf94aa89294b19c0496bdbe84d18
(cherry picked from commit de9fa5074e)
avoids int rollover when working with large input
BUG=webp:312
Change-Id: I3d7b689be8d5751248a82d1021243d80d3f67203
(cherry picked from commit deb1b83199)
the min-distortion was quite too low. And we were also
considering the fully skipped macroblocks (nz=0) in the stats.
We need to have at least *some* non-zero dc coeffs (nz=0x100XXXX).
Fix also two typos in StoreMaxDelta: the v0/v1 comparison was wrong,
and the DCs[] coeffs are actually already in ZigZag order.
Change-Id: I602aaa74b36f7ce80017e506212c7d6fd9deba1f
Make WebPPictureDistortion() only compute distortion on A/R/G/B planes, not Y/U/V(A).
(not just for SSIM, but PSNR too).
This is to avoid problems with using SSIM on U/V channels.
If Y/U/V distortion is needed, one can always use WebPPlaneDistortion() individually.
Change-Id: If8bc9c3ac12a8d2220f03224694fc389b16b7da9
When compiling as experimental, WEBP_EXPERIMENTAL_FEATURES
would not be defined because the header defining it would
not be included.
Hence runtime errors in debug mode when running:
./cwebp -lossles whatever
...
Error! Cannot encode picture as WebP
Error code: 4 (INVALID_CONFIGURATION: configuration is invalid)
(detail: WebPConfig would have a random value set for
delta_palettization as config.c does not consider
it to exist.)
Change-Id: I41761cffe81a971130ed514b195a73d1c6dac1b7
