(implements the backward and forward transforms in the encoder)
original patch by Wayne Chen (datoudatou at gmail dot com)
Change-Id: Ic00f3bffcdf7a924f043006728735c810ee47a57
- Changed the dynamic range where more aggressive
(BackwardReferencesTraceBackward) heuristic is run from quality > 10
(instead of quality > 25).
- Limit the backward-ref Window size to 16*width & 256*width for lower
qualities ([0, 25[ & [25, 50[) respectively, instead of 1M window.
- Evaluate the params for HashChainFindCopy outside this function call
and pass it, instead of recomputing them for every call.
Change-Id: If9eedfc14b978e7632d7cf69c96186e2910b0554
the max wasn't checked leading to a rollover case, possibly exploitable.
additionally check the RIFF size early, to avoid similar issues.
pulled from chromium:
http://codereview.chromium.org/11229048/
Change-Id: I4050b13a7e61ec023c0ef50958c45f651cf34c49
Query the converter to ensure the format is supported; add BGR formats
as RGBA was failing for PNG on XP
Fixes issue 129
Change-Id: Ib42aaf160a6c18e767e8c7dbe93dec7c45953399
correct has_alpha check; previously it was controlled by keep_alpha,
which overrode the source format check.
fixes issue #127
Change-Id: I414cfd9c5ed60b13673ccd2262ee5e4505ed6f6a
the multiplications done for total_size would be done with integers,
possibly overflowing, before being promoted to 64-bit for the addition
Change-Id: I32c3a6400fc2ef120c38e01a8693f4cb1727234d
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: I0f20cee98c29b2b40b02607930b6b7a7ca56996d
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: I053e6d340850f02761687e072b0782c6734d4bf8
this will avoid the "dec_neon.o has no symbol" warning
no change in binary size observed on linux.
Change-Id: Ifd83dfc6a0c61905481599b06cb5e711f55efa7d
the max wasn't checked leading to a rollover case, possibly exploitable.
additionally check the RIFF size early, to avoid similar issues.
pulled from chromium:
http://codereview.chromium.org/11229048/
Change-Id: Ifebc712bf3d3de0129b76ca4c57c68e062abc429
Query the converter to ensure the format is supported; add BGR formats
as RGBA was failing for PNG on XP
Fixes issue 129
Change-Id: I02e0d74b3b21337bc5fffd6a5dc158b7809b9aa9
This is mostly for experimentation!
Need to define USE_YUVj flag in the code for that.
suggested by benwreder at hotmail dot com
Change-Id: If0b8e2c1863efc08ce097de6de20f4c7efc3f7e8
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
