The patch 21735e0 introduced a bug where a goto path was not testing
the eos_ state. If this happened just before a row_sync, a SaveState()
would be called that would store the eos_ state as '1' till the end
of the loop. This usually was not a problem, except for the very last
chunk where we disable the incremental decoding altogether (we have all
the data). The termination tests were then going wrong.
The fix is to add a proper eos_ test and avoid falling in this inconsistent
state.
(21735e06f7)
BUG=webp:332
Change-Id: Ib16773aee26bfd068fbf4e9db3d2313bd978b269
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
This code is ultra-critical for lossless decoding, especially on ARM.
The extra call VP8LIsEndOfStream() was causing unnecessary slow-down.
Now, we check for bitstream-end separately in the main loop.
Change-Id: I739b5d74cc29578e2b712ba99b544fd995ef0e0d
Currently, none are available. If WEBP_HAVE_SSE2 eventually works,
we'll have to refine this conditionals.
BUG=webp:261
Change-Id: Ibc63ee1c013f2a4169eeb85cc8b6317b6420c2ad
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
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)
Compile with XCode, it appears quite slower than the C-version,
especially for arm64.
Change-Id: Ic46dba184a36be454fef674129d2f909003788fc
(cherry picked from commit 4f3e3bbd44)
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
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
We can switch at run-time between the standard GetCoeffs() critical
function, that uses a fast variant of VP8GetBit().
However, some platforms have slow instructions that make standard
VP8GetBit() slow. GetCoeffs() is the right level of branching to
switch to GetCoeffsAlt() that avoids these slow instructions in some
not-frequent cases.
Next patch will upgrade VP8GetBit() to use clz, after this one
is proved to be neutral speed-wise.
Change-Id: Ia6cef5de9de6131574d2202bbc0bea8559c9b693
vmlal_u8() is prone to overflow during the accumulation.
There was a mismatch happening at low q mostly. Because in this
case the distortion is important and the accumulated sum was
later than 16bit-unsigned.
Change-Id: I1a08a2f744bcdf0b26647e61b9ee92a0c2e28fe8
This makes the structure more generic, without the hard-coded
internal structure.
This is a borderline incompatible ABI change, even if WebPIDecoder structure
is opaque.
Change-Id: I518765c3f76fc17a136cef045a5a8aa70ed70e85
30% faster on x86, 5% faster on N5.
New generic function: WebPLog2FloorC()
This function is called as fallback for BitsLog2Floor() when there's
no clz() available.
Change-Id: Ica15c6092112e514c0e200fab89c434de48d4b19
This is meant to be used for run-time detection of slow platforms
regarding instructions like pshufb and bsr.
Adapted from libvpx patch: https://chromium-review.googlesource.com/#/c/367731
Change-Id: I2c22fbb9aae699d87a041393ba1ad5f1f21ff640
and 15% faster MultARGBRow()
by switching to formulae:
X / 255 = (X + 1 + (X >> 8)) >> 8 for any 16bit value X.
(X / 255 + .5) = (XX + (XX >> 8)) >> 8, with XX = X + 128
Change-Id: Ia4a7408aee74d7f61b58f5dff304d05546c04e81
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
In GenerateCandidates(), when candidate_ll->evaluate_ and
candidate_lossy->evaluate_ are both true, if lossless encoding
exits on error, candidate_ll->evaluate_ would not be correctly
reset. This will cause freeing uninitialized memory pointer in
SetFrame().
BUG=webp:322
Change-Id: I481b49a186e4fa3607ce71b4543a481083edf444
(cherry picked from commit 3ebe1c0003)
This improves compression by ~5% at default quality.
If only 'allow_mixed' is on (but 'minimize_size' isn't), we continue to
use a heuristic to try one of the two or both.
Change-Id: Ia573a73ea26ad25f9debff759eed69d2b0449e82
(cherry picked from commit 3f4042b52a)
In GenerateCandidates(), when candidate_ll->evaluate_ and
candidate_lossy->evaluate_ are both true, if lossless encoding
exits on error, candidate_ll->evaluate_ would not be correctly
reset. This will cause freeing uninitialized memory pointer in
SetFrame().
BUG=webp:322
Change-Id: I481b49a186e4fa3607ce71b4543a481083edf444
after:
fbba5bc optimize predictor #1 in plain-C For some reason, gcc has hard
time inlining this one...
Change-Id: I2e2416593acd4c9d14958d8757bfd284d999100b
For some reason, gcc has hard time inlining this one...
Also optimize predictor #0 and #1 for encoding, so we don't have to
call the generic pointers VP8LPredictors[...]
Change-Id: I1ff31e3b83874b53f84fe23487f644619fd61db9
Set enc->prev_candidate_undecided_ as 0 when a frame is not chosen
as a possible keyframe, so that the dispose method can be
dispose-to-background.
Change-Id: If2899f5dbc06fb53705fb8240072ab6440a6de12
(cherry picked from commit 29fedbf58b)
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)
some multiplies here and there needed some extra checks
and error reporting. Even if width * height is guaranteed
to be < 2**32, we were multiplying by num_channels and
triggering a 32b overflow.
Some multiplies were not using size_t or uint64_t, additionally.
Change-Id: If2a35b94c8af204135f4b88a7fd63850aa381bbf
(cherry picked from commit 1c36440094)
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)
