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
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
SSIM results are incompatible with previous version!
We're now averaging the SSIM value for each pixels instead of
printing a frame-level global SSIM value.
* Got rid of some old code
* switched to uint32_t for accumulation
* refactoring
SSIM calculation is ~4x faster now.
Change-Id: I48d838e66aef5199b9b5cd5cddef6a98411f5673
-print_psnr is now much faster because it doesn't use the SSIM code.
The SSIM speed-up and re-write will come later.
Change-Id: Iabf565e0a8b41651d8164df1266cfeded4ab4823
we don't need to centralize best_uv[] since target_uv[] and best_rgb_uv[]
are already centralized. The diff 'W' was just in the ~[-2,2] range, so
we can ignore the correction.
Overall speed-impact is not large, though. Around ~4% faster conversion.
Output with -pre 4 is expected to be slightly different
Change-Id: Ib59f033955577c49b084d0560108020f42d84102
also: remove the useless clipping in StoreGray()
For speed reason, the 'gray' plane was initialized with the same
value for 2x2 block. But in some cases (underlying camera noise, e.g.),
it could lead to instability during iteration, noise amplification,
and visible banding.
Using a precise (but slower) initialization solves the issue, and
since the convergence is faster, we might actually gain some speed.
Change-Id: I81c42101497e7096a8f60289d710f5a3bcb0ddea
We usually need at least 2 iterations to converge
(and usually not much more after that). Only 1 was not enough.
Change-Id: Iaf802ea81afa2596f4ba045c92f5eaff61623b7b
No need to find backward references for pixels in uniform regions
by looking at all pixels.
Only pixels at the same distance from the end need to be compared to.
Change-Id: I4f187e965f0667d3a929775726a412f7e69f6473
Constants are such that brute force is sometimes faster for some
data (mostly big images it seems).
Change-Id: I90aef536408683535e3b09ddfa2e77a9834038f6
Return key/index if the query is found, and -1 otherwise.
The benefit of this is to save a hashing computation.
Change-Id: Iff056be330f5fb8204011259ac814f7677dd40fe
The decision is based on the variance between DC values of each
sub-4x4 block. This heuristic is rather ok for predicting whether
the 2nd transform (intra-16) is going to help or not.
The decision threshold varies with quality (=quantization).
It's only used for -m 0 and -m 1, where no full RD-opt is performed.
It actually makes these modes quite faster, with RD curve much
closer to the -m 2 mode.
Change-Id: I15f972db97ba4082cbd1dfd16bee3eb2eca701a8
- 6/14/2016: version 0.5.1
This is a binary compatible release.
* miscellaneous bug fixes (issues #280, #289)
* reverted alpha plane encoding with color cache for compatibility with
libwebp 0.4.0->0.4.3 (issues #291, #298)
* lossless encoding performance improvements
* memory reduction in both lossless encoding and decoding
* force mux output to be in the extended format (VP8X) when undefined chunks
are present (issue #294)
* gradle, cmake build support
* workaround for compiler bug causing 64-bit decode failures on android
devices using clang-3.8 in the r11c NDK
* various WebPAnimEncoder improvements
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Merge tag 'v0.5.1'
libwebp-0.5.1
- 6/14/2016: version 0.5.1
This is a binary compatible release.
* miscellaneous bug fixes (issues #280, #289)
* reverted alpha plane encoding with color cache for compatibility with
libwebp 0.4.0->0.4.3 (issues #291, #298)
* lossless encoding performance improvements
* memory reduction in both lossless encoding and decoding
* force mux output to be in the extended format (VP8X) when undefined chunks
are present (issue #294)
* gradle, cmake build support
* workaround for compiler bug causing 64-bit decode failures on android
devices using clang-3.8 in the r11c NDK
* various WebPAnimEncoder improvements
* tag 'v0.5.1': (30 commits)
update ChangeLog
Clarify the expected 'config' lifespan in WebPIDecode()
update ChangeLog
Fix corner case in CostManagerInit.
gif2webp: normalize the number of .'s in the help message
vwebp: normalize the number of .'s in the help message
cwebp: normalize the number of .'s in the help message
fix rescaling bug: alpha plane wasn't filled with 0xff
Improve lossless compression.
'our bug tracker' -> 'the bug tracker'
normalize the number of .'s in the help message
pngdec,ReadFunc: throw an error on invalid read
decode.h,WebPGetInfo: normalize function comment
Inline GetResidual for speed.
Speed-up uniform-region processing.
free -> WebPSafeFree()
DecodeImageData(): change the incorrect assert
Fix a boundary case in BackwardReferencesHashChainDistanceOnly.
Make sure to consider small distances in LZ77.
add some asserts to delimit the perimeter of CostManager's operation
...
Change-Id: I44cee79fddd43527062ea9d83be67da42484ebfc
This is essentially a revert of a3611513d2
and cfbcc5ece0.
Here is what happened: there was a corruption bug that eventually
got fixed by 0174d18d8b.
But before finding the root, a3611513d2
and cfbcc5ece0 hid the bug
by not imposing length of 1 when it was actually 2 or 3 (which does help
compression as a litteral is more efficient than an offset and a length
of size 2 or 3).
Change-Id: I6f18fc1f583a51ac9d8aab2508458264047cd493
We only perform a single pass, and swap the final histograms
into the beginning of the array as we go. Therefore, they are
already at the correct place at the end of the pass.
-> HistogramCompactBins() is removed, we just truncate the array.
output is bitwise the same.
Change-Id: I9508c96dda0f8903c927a71b06af4e6490c3249c
output should bit-write the same as before, in both
low_effort and non low_effort modes.
if anything, speed is a tad faster, probably because of the
reduced memory traffic.
Change-Id: Iaa2ddcfda2aaffefe7e5b7bc89216373d1ddb194
The optimization for (len != MIN_LENGTH) actually only holds for
(len > MIN_LENGTH) but (len < MIN_LENGTH) can now happen as len can
be changed in the loop before.
Change-Id: I3f9f91a540206c80385c5fba96c3d64ab9536752
This is getting back to the old behavior which is actually better for
compression and speed with the latest patches.
Change-Id: I35884bab02589297c25d6e1e66dc5f13e05f7aa7
This was defined (slightly differently) at two places. Created a common
method and moved to utils/utils.[hc].
Change-Id: I66c3ac6dea24e0cd2c0eaa5440f3142b4dbbe23b
we don't need to store the resulting histogram, so no need to
call HistogramAddEval().
Allows some signature simplifications...
Change-Id: I3fff6c45f4a7c6179499c6078ff159df4ca0ac53
