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
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
Return key/index if the query is found, and -1 otherwise.
The benefit of this is to save a hashing computation.
Change-Id: Iff056be330f5fb8204011259ac814f7677dd40fe
pre-allocating a sorted[] array for most common cases of small
alphabet size cuts a lot of traffic.
Change-Id: I73ff2f6e507f81b0b0bb7d9801a344aa4bcb038a
MAX_COLOR_COUNT was just a synonym and its use in the header was a bit
strange given the visibility of that define.
Change-Id: I536964ddc14a0c48263191b6afb80695b5a038e6
This was defined (slightly differently) at two places. Created a common
method and moved to utils/utils.[hc].
Change-Id: I66c3ac6dea24e0cd2c0eaa5440f3142b4dbbe23b
This reverts commit 169004b1d5.
this changes the ABI, so should bump versions and add a note to NEWS
when we're ready to expose it
Change-Id: Ic5bbd0aee2b6fd0f9d438a9effedf22fe0cec4bf
This was defined (slightly differently) at two places. Created a common
method and moved to utils/utils.[hc].
Change-Id: I19adc9c48f2a4e2ec9d995e78add6f25172774c2
no longer gate this on WEBP_FORCE_ALIGNED as WebPMemToUint32() provides
this service. replace that check with WORDS_BIGENDIAN as the block is
currently little-endian specific.
Change-Id: Ie04ec0179022d20dab53da878008ae049837782f
the read size may be fixed, but the offsets into buf_ are not. forcing
an aligned read then shifting or using a temporary would be costly. this
is less important now that WebPMemToUint32() is being used.
Change-Id: I357fec8f750969cce91987abebed2f95e27a835f
add WEBP_UBSAN_IGNORE_UNDEF to WebPMemToUint32() / WebPUint32ToMem()
when WEBP_FORCE_ALIGNED is unset
Change-Id: I726b2e708ce29681584eb10c8874d5cf1e798756
include utils.h directly where needed to allow utils.h to rely on
defines from dsp.h in a follow-up.
Change-Id: I32e26aaeb0b04ba60b3332f685f9a2be5a0a8d3d
and also pass 'VP8Io* io' extra param to VP8DecompressAlphaRows()
This is somehow in preparation for some memory optimizations in
the 'cropping' case. For now, only the easy crop_bottom case is
optimized.
Change-Id: Ib54531ba057bf62b98422dbb6c181dda626c72c2
* changes:
Makefile.vc: enable WEBP_USE_THREAD for windows phone
thread: use CreateThread for windows phone
thread: use WaitForSingleObjectEx if available
thread: use InitializeCriticalSectionEx if available
thread: use native windows cond var if available
the original change triggered several internal API modifs.
This is to ensure that we're never computing pointer that can
possibly wrap around, or differences between pointers that can
overflow.
no observed speed difference
Change-Id: I9c94dda38d94fecc010305e4ad12f13b8fda5380
We now consider 3 special cases:
* htree-group has only 1 code (no bit is read from bitstream)
* htree-group has few enough literal symbols, so that all the bit
codes can fit into a look-up table of less than 64 entries
* htree-group has a trivial arb literal (not GREEN!), like before
No overall speed change.
Change-Id: I6077fa0b7e5c31a6c67aa8aca859c22cc50ee254
Note that ALIGN_CST is still kept different in dec/frame.c for now,
because the values is 31 there, not 15. We might re-unite these two
later.
Change-Id: Ibbee607fac4eef02f175b56f0bb0ba359fda3b87
The rounding and arithmetic is not the same as previously, to prevent overflow cases for large upscale factors.
We still rely on 32b x 32b -> 64b multiplies. Raised the fixed-point precision to 32b
so that we have some nice shifts from epi64 to epi32.
Changed rescaler_t type to 'uint32_t' in order to squeeze in all the precision required.
The MIPS code has been disabled because it's now out-of-sync. Will be fixed in
a subsequent CL when the dust settles.
~30-35% faster
Change-Id: I32e4ddc00933f1b1aa3463403086199fd5dad07b
* vertical expansion now uses bilinear interpolation
* heavily assumes that the alpha plane is decoded in full, not row-by-row
* split the RescalerExportRow and RescalerImportRow methods into Shrink
and Expand variants.
* MIPS implementation of ExportRowExpand is missing.
There's room for extra speed optim and code re-org, but let's keep that for later patches.
addresses https://code.google.com/p/webp/issues/detail?id=254
Change-Id: I8f12b855342bf07dd467fe85e4fde5fd814effdb
allows the values to be used in preproc checks, fixing a
-Wunreachable-code warning in 64-bit builds where VP8L_WRITER_BITS != 16
Change-Id: Ie98dff4e8ef896436557c64d5da2c5d70228a730
the x_add/x_sub increments were wrong for u/v in the upscaling case.
They shouldn't be left to the caller's discretion, but set up by
WebPRescalerInit to their exact necessary values.
-> Cleaned-up WebPRescalerInit() param list.
-> added safety asserts
-> removed the mips32/mips_r2 variant of "ImportRow" which were buggy prior
Change-Id: I347c75804d835811e7025de92a0758d7929dfc09
valgrind --tool=callgrind shows a 9 % speedup: 1021201984 ticks before vs.
927917709 after
-q 0 -m 0 -lossless ~/alpi/1.png
22.040 MP/s before
24.796 MP/s after
Change-Id: Iaab928167b3e20fb0d9401c6f8317a26c5a610b4
_BitScanReverse() takes an unsigned long*
http://msdn.microsoft.com/en-us/library/fbxyd7zd.aspx
fixes:
C4057: 'function': 'unsigned long *' differs in indirection to slightly
different base types from 'uint32_t *'
fixes issue #253
Change-Id: I0101ef7be18c7ed188b35e9b17e7f71290953786
this should be used in preference to free() for releasing memory
returned from WebPDecode*() / WebPEncode*(). this simplifies memory
management when working through language bindings
Change-Id: I15eb538a45390efc552fda8e5c251a3fbdc13c29
* make VP8LPrefetchBits() safe wrt past-EOS reads
* set 'BitReader::bits_" to a safe shifting value upon EOS
no visible performance difference on x86
Change-Id: I0a4177928cfa81d5dfc9054b36a686eaa1bf8c65
quiets an msvs /analyze warning, the cast is due to an earlier msvs
build warning.
C6297: Arithmetic overflow: 32-bit value is shifted, then cast to
64-bit value. Results might not be an expected value.
Change-Id: I0bb6cda57879f2fbd1e3515f6753a11bc08d14ac
histogram.c:
- Verified (earlier) that there's low correlation between Red & Blue colors
(particularly after applying Cross-color transform). The Bin based histogram
merge, bins on three entropies viz literal, red & blue symbols. Removing
either of blue or red increases the compression density. So keeping the bins
for red & blue sybmols.
- Keeping the compact bins method as-is. This way it's simpler to read.
huffman_encode.h: Added field comments for struct HuffmanTree and removed the TODO.
Change-Id: Ia76f7bc730079d1b3b644038c5d9931db3797f0e
* We don't need to change DecodeAlpha, since incremental
decoding is not useful for Alpha (we already decode
progressively along the RGB)
* Similarly, we don't do incremental decoding for level>0 planes:
the metadata don't turn into visible pixel (only the ones in level0), so...
(No visible speed change)
Change-Id: I2fd4b9ba227561a7dbede647686584b752be7baa
Optimize the decoding for region that have trivial literal codes.
The trivial literal is defined as huffman image with Red, Blue and Alpha
huffman trees with only single code values.
This speeds up lossless decoding by 3%
Change-Id: I0204949917836f74c0eb4ba5a7f4052a4797833b
ReadSymbol() finishes with a VP8LSetBitPos() call only and could miss an eos_ during the decode loop.
Things are faster because of inlining too.
Change-Id: I2d2a275f38834ba005bc767d45c5de72d032103e
eos_ needs to be set only when superfluous bits have actually
been requested.
Earlier, we were assuming pre-mature end-of-stream to be an error.
Now, more precisely, we mark error when we have encountered end-of-stream *and*
we attempt to read more bits after that.
This handles cases where image data requires no bits to be read
Change-Id: I628e2c39c64f10c443fb51f86b1f5919cc9fd299
speed-up is ~1.6% for photographic image to 10% for graphical image
(1000 images corpus was sped up by 5.8 %)
Code by akramarz@google.com and jyrki@google.com
Change-Id: Iceb2e50e6cc761b9315a3865d22ec9d19b8011c6
if a thread was still doing work when End() was called there'd be a race
on worker->status_. in these cases, however, the specific value is
meaningless as it would be >= OK and the thread would have been shut
down properly, but we'll check 'impl_' instead to avoid any potential
TSan/DRD reports.
Change-Id: Ib93cbc226a099f07761f7bad765549dffb8054b1
defines HAVE_BUILTIN_BSWAP16/32/64
updated endian_inl.h to have a non-configure fallback for gcc and clang
BSwap16() now uses __builtin_bswap16 if available
Change-Id: Ia04ee07b39303c4b247df96d84f298fb8a81f389
also reduce the load size from 64 to 32 bits as the top 32 bits are
being shifted away in the operation.
the change is neutral speed-wise on x86_64 as is the change in load size
on x86, but it gives a slight improvement on 32-bit arm.
x86 is improved ~13%, 32-bit arm ~3.7%
aarch64 is untested but will likely benefit as well.
Change-Id: Ibcb02a70f46f2651105d7ab571afe352673bef48
forces aligned memory reads (via memcpy) in the VP8 bit reader, useful
for platforms that don't support unaligned loads.
Change-Id: Ifa44a9a1677fbdc6a929520f9340b7e3fcbd6692
