LSIM stands for "local similarity": before matching
a compressed pixel to the source, we search around in the source
and minimise the squared error. So, this is close to PSNR calculation,
but mitigates some of its limitations (pure translation and noise for instance).
There's a new -print_lsim option to cwebp too.
Change-Id: Ia38561034c7a90e71d2ea0f55bb1de527eda245b
Make the heuristic for combining Histograms a function of compression
quality. This change will speed-up compression time for compression
quality less than 75. The compression time/density remains unchanged
for compression quality 75 and higher.
Change-Id: I94513d51078340fbc0737d459fab2cebdd2d6082
correct has_alpha check; previously it was controlled by keep_alpha,
which overrode the source format check.
fixes issue #127
Change-Id: I949be90419b03610c64900be0fd37f83b70cbe73
the multiplications done for total_size would be done with integers,
possibly overflowing, before being promoted to 64-bit for the addition
Change-Id: Id5c127c8a497ce5de89a276c17f36b59eeb67c21
huff_image_size was a size_t (=32 bits with 32-bit builds) which could
rollover causing an incorrectly sized allocation and a crash in lossless
encoding.
fixes issue #128
Change-Id: I175c8c6132ba9792034807c5c1028dfddfeb4ea5
in debug mode, some float operations see their intermediate
values stored in memory rather than staying in the FPU (which
is 80bit precision).
Several fixes are possible (breaking long calculations into
atomic steps for instance), but simpler of all is just about
turning the cost[] array into float* instead of double*.
The code is a tad faster, and i didn't see any major output
size difference.
Change-Id: Icf1f833e15f8ee4ecc7f9a521d07fdc96ef711aa
Change-Id: I36d3765e94d2b5529b321c186ccee1744785c5b3
fixes:
error: ISO C++ forbids forward references to 'enum' types
since:
28d25c8 replace 'typedef struct {} X;" by "typedef struct X X; struct X {};"
Returning 0 (equal) can lead to undefined behaviour.
And, in our cases we'll never have equal keys (added asserts for that)
Change-Id: Ifaf202df321d3f877ad2a03de42e0d6cdd1b2388
SBITS=8 is reported 20-30% faster on ARM (where 64bit ops
are expensive).
Also use 32bits for i32.
Change-Id: Id6a7197d805061aeb8832f20432512d0d930ebfa
fixes the 'blocky sky problem' (saturation problem: when luma was flat,
chroma noise was taking over, resulting in random segment id assigned.
When just using a common uniform segment was better).
+ side clean-up and readibility/experimentability MACRO'ization
+ added '-map 7' option
Change-Id: I35982a9e43c0fecbfdd7b05e4813e8ba8c121d71
this will avoid the "dec_neon.o has no symbol" warning
no change in binary size observed on linux.
Change-Id: Ia27ae2bc5a03d714afa7e46671fdcf4cb630784d
* 0.2.0: (42 commits)
Update ChangeLog
dec/io.c: cosmetics
RGBA4444: harmonize lossless/lossy alpha values
fix RGBA4444 output w/fancy upsampling
Alignment fix
avoid rgb-premultiply if there's only trivial alpha values
fix the ARGB4444 premultiply arithmetic
Lossless decoder fix for a special transform order
Update encoding heuristic w.r.t palette colors.
remove unused ApplyInverseTransform()
Update ChangeLog
update AUTHORS
update NEWS
add support for ARGB -> YUVA conversion for lossless decoder
bump version to 0.2.0
fix alpha-plane check + add extra checks
MODE_YUVA: set alpha to opaque if the image has none
silence one more warning
move some RGB->YUV functions to yuv.h
README: sync [cd]webp help output
...
Change-Id: I4c4e3be2e88655d25d4dd2eae46c580d960b12ac
lossy was rounding with a bias toward opaque:
[232+, 8] -> [15, 1]
now both paths use the range:
[240+, 16] -> [15, 1]
Change-Id: I3da2063b4959b9e9f45bae09e640acc1f43470c5
With this, MODE_rgbA can safely be used without speed penalty
even in case of pure-lossy alpha-less input.
It's also an optimization when cropping a fully-opaque region from
an image with alpha: premultiply is then skipped
Change-Id: Ibee28c75744f193dacdfccd5a2e7cd1e44604db6
* green was not descaled properly
* alpha was over-dithered, making the value '0x0f' not be a fixed point
* alpha value was not restored ok.
Change-Id: Ia4a4d75bdad41257f7c07ef76a487065ac36fede
