check enc->argb_ to quiet an msvs /analyze warning:
C6387: 'enc->argb_+y*width' could be '0': this does not adhere to the
specification for the function 'memcpy'.
Change-Id: I87544e92ee0d3ea38942a475c30c6d552f9877b7
Disable costly TraceBackwards heuristic for computing the backward references
for low_effort (method=0) compression.
The TraceBackwards heuristic is already disabled for lower (q < 25) quality
range. Following is the compression data for 1000 image corpus for q >= 25.
This speeds up compression (q >= 25) by a factor of 2.5-3X with slight loss of
compression density (0.7% for lower quality range and 1.2% for higher qualities).
Change-Id: I256c9e2137c7de4083f423ea32ee12d3b0f46253
- Lower the threshold parameters for HashChainFindCopy.
For 1000 image PNG corpus (m=0), this change yields speedup of 15-20% at
lower quality range (0.25% drop in compression density) and about 10%
for higher quality range without any drop in the compression density.
Following is the compression stats (before/after) for method = 0:
Before After
bpp/MPs bpp/MPs
q=0 2.8615/18.000 2.8651/18.631
q=5 2.8615/18.216 2.8650/20.517
q=10 2.8572/18.070 2.8650/21.992
q=15 2.8519/18.371 2.8584/21.747
q=20 2.8454/18.975 2.8515/20.448
q=25 2.8230/8.531 2.8253/9.585
// Compression density remains same for q-range [30-100]
q=30 2.7310/7.706 2.7310/8.028
q=35 2.7253/6.855 2.7253/7.184
q=40 2.7231/6.364 2.7231/6.604
q=45 2.7216/5.844 2.7216/6.223
q=50 2.7196/5.210 2.7196/5.731
q=55 2.7208/4.766 2.7208/4.970
q=60 2.7195/4.495 2.7195/4.602
q=65 2.7185/4.024 2.7185/4.236
q=70 2.7174/3.699 2.7174/3.861
q=75 2.7164/3.449 2.7164/3.605
q=80 2.7161/3.222 2.7161/3.038
q=85 2.7153/2.919 2.7153/2.946
q=90 2.7145/2.766 2.7145/2.771
q=95 2.7124/2.548 2.7124/2.575
q=100 2.6873/2.253 2.6873/2.335
Change-Id: I0e17581fb71f6094032ad06c6203350bd502f9a1
- Do light weight entropy based histogram combine and leave out CPU
intensive stochastic and greedy heuristics for combining the
histograms.
For 1000 image PNG corpus (m=0), this change yields speedup of 10% at
lower quality range (1% drop in compression density) and about 5% for
higher quality range (1% drop in compression density). Following is the
compression stats (before/after) for method = 0:
Before After
bpp/MPs bpp/MPs
q=0 2.8336/16.577 2.8615/18.000
q=5 2.8336/16.504 2.8615/18.216
q=10 2.8293/16.419 2.8572/18.070
q=15 2.8242/17.582 2.8519/18.371
q=20 2.8182/16.131 2.8454/18.975
q=25 2.7924/7.670 2.8230/8.531
q=30 2.7078/6.635 2.7310/7.706
q=35 2.7028/6.203 2.7253/6.855
q=40 2.7005/6.198 2.7231/6.364
q=45 2.6989/5.570 2.7216/5.844
q=50 2.6970/5.087 2.7196/5.210
q=55 2.6963/4.589 2.7208/4.766
q=60 2.6949/4.292 2.7195/4.495
q=65 2.6940/3.970 2.7185/4.024
q=70 2.6929/3.698 2.7174/3.699
q=75 2.6919/3.427 2.7164/3.449
q=80 2.6918/3.106 2.7161/3.222
q=85 2.6909/2.856 2.7153/2.919
q=90 2.6902/2.695 2.7145/2.766
q=95 2.6881/2.499 2.7124/2.548
q=100 2.6873/2.253 2.6873/2.285
Change-Id: I0567945068f8dc7888041e93d872f9def91f50ba
inline function MakeARGB32 calls changed to call
via pointers to functions which make (a)rgb for
entire row
Change-Id: Ia4bd4be171a46c1e1821e408b073ff5791c587a9
most of the time, we don't need to actually move the
data.
Compression is randomly slightly different, because HistogramCompactBins() changed.
Timing is about the same.
Change-Id: Ia6af8e9780581014d6860f2b546189ac817cfad1
we don't need to store the whole distribution in order to compute the alpha
Later, we can incorporate the max_value / last_non_zero bookkeeping
in SSE2 directly.
Change-Id: I748ccea4ac17965d7afcab91845ef01be3aa3e15
this is a first step to unifying encoding/decoding cache stride
and possibly sharing the prediction functions in dsp/
With this layout, there's a little (~7%) space lost with unused samples.
But no speed change was observed.
Change-Id: I016df8cad41bde5088df3579e6ad65d884ee711e
Move all the Entropy evaluation methods to lossless.c (from histogram.c).
There's slight difference in the way entropy is computed for evaluating
entropy in prediction methods and histogram (literal) for huffman trees.
Plan (later) to merge few (static) methods and reduce the code size.
This change has no impact on the compression speed/density.
Change-Id: Ife3d96a3c4a8d78a91723d9e0a8d1b78c0256a15
Remove handling for WEBP_HINT_GRAPH w.r.t use_palette flag.
The WEBP_HINT_GRAPH is now used at one place, to set the initial size of the
Bit Writer as bpp for photo images are generally larger than the graphical
images.
Change-Id: I1b9c4436c85a8f69da74c0dbcd292397323f2696
Update BackwardRefsWithLocalCache to do in-place update of backward
references w.r.t local color cache index.
No impact on the compression density or compression speed.
Change-Id: Ie066251464c3928c044e037b43df3af28b48ca30
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
Use the refs_lz77 computed (with cache_bits=0) in the method 'CalculateBestCacheSize'
to regenerate the LZ77 references corresponding to the optimum cache_bits and avoid
calling costly 'BackwardReferencesLz77' one extra time.
This change leaves the compression density unchanged and speeds up compression
by 10-15%.
Change-Id: I5a92e11788d3c3f656aa7e1fba54fb5d96ee0027
This wasn't working for this specific scenario:
- Encode an RGBA 'pic' (with trivial alpha) using lossy encoding.
(so that pic->a == NULL after import happens).
- Modify the 'pic->argb' so that it has non-trivial alpha.
- Encode the same 'pic' again.
This used to fail to encode alpha data as pic->a == NULL.
Change-Id: Ieaaa7bd09825c42f54fbd99e6781d98f0b19cc0c
- The optimal cache bits is evaluated inside the method 'VP8LGetBackwardReferences'.
- The input cache_bits to 'VP8LGetBackwardReferences' sets the maximum cache
bits to use (passing 0 implies disabling the local color cache).
- The local color cache is disabled for lowerf (<= 25) quality levels (as before).
- Enabled local color cache for palette images as well. This saves additional
0.017% bytes with a slight (2-3%) improvement in the compression speed.
- Removed 'use_2d_locality' parameter from method VP8LGetBackwardReferences, as
this option is not an option now (after we freeze the lossless bit-stream).
Change-Id: I33430401e465474fa1be899f330387cd2b466280
Updated BackwardReferencesRle method by utilizing the local color cache.
Also changed the name of method BackwardReferencesHashChain to
BackwardReferencesLz77 to reflect the LZ77 coding.
For the 1000 image corpus, this change saves 0.2% bytes
(at default settings) and is 2-5% faster to encode.
Change-Id: Ic3f288253b3bbb101a69945a80994c3fd0917f8b
Optimize backwardreferences (about 0.1% byte savings) with almost same
compression speed (3% faster on defaut compression settings).
1.) Simplified iteration logic for HashChainFindCopy.
- Remapped the iter_max constant.
2.) Simplified main for loop for BackwardReferencesHashChain
- Removed 'if' conditions for corner cases in the main loop.
- Refactored the method(AddSingleLiteral) for adding one pixel.
Change-Id: I1bc44832fd81f11e714868a13e606c8f83157e64
Speed up BackwardReferencesHashChainDistanceOnly method by:
1.) Remove for loop for shortmax code path.
2.) Execute the shortmax code path after regular call to
HashChainFindCopy, only if HashChainFindCopy() returns length > 2 (MIN_LENGTH).
3.) Also for shortmax, call method HashChainFindOffset (for length = 2),
instead of expensive method HashChainFindCopy().
4.) Handling first pixel (i==0) outside main loop and removing one if
condition (i > 0) per pixel.
5.) Handle the last pixel outside the main 'for' loop.
Overall compression speedup observed is around 5% (+/- noise).
Change-Id: Ifa30c4035f8d26e6e43e3c4881244d777961c22b
Enable bin-partition entropy based heuristic for merging histograms
for higher (q >= 90) qualities as well. Keep the old behavior at the
maximum quality level (q==100).
This speeds up the compression between Q=90-99 (method=4) by factor 5-7X
and with loss of 0.5-0.8% in the compression density.
Change-Id: I011182cb8ae5403c565a150362bc302630b3f330
The Maximum allowed limit is 11.
The Q=25 and below is not impacted as cache bits are forced to 0.
This saves 0.05% - 0.1% bytes for other quality with almost same compression
speed (+/- 2-3%, that's more of a noise).
Change-Id: Icf972a98f298c89e140e37a627baf709134be9a0
Updated the logic to limit the Histogram size to a constant, instead of
computing the same based on the Histogram size (that's variable size based on
the cache bits) for the maximum possible cache bits. The actual cache bits may
be lower than the maximum.
Note: The constant 2600 is 16MB/Sizeof(HistogramSize(MAX_COLOR_CACHE_BITS)).
The compression density remains the same with this change, with little faster
compression speed.
Change-Id: I3149894962852e9dad2501b9aa16bb847a20fd86
The method VP8LCalculateEstimateForCacheSize is not evaluating the all possible
range for cache_bits.
Also added a small penality for choosing the larger cache-size. This is done to
strike a balance between additional memory/CPU cost (with larger cache-size) and
byte savings from smaller WebP lossless files.
This change saves about 0.07% bytes and speeds up compression by 8% (default
settings). There's small speedup at Q=50 along with byte savings as well.
Compression at Quality=25 is not effected by this change.
Change-Id: Id8f87dee6b5bccb2baa6dbdee479ee9cda8f4f77
Instead of calling HashChainFindMethod, call a new (subset) method
HashChainFindOffset to get the offset/distance for a given length.
The encoding is tad faster at default compression
Before After
bpp/rate bpp/rate
442 Palette 0.2720/5.270 MP/s 0.2720/5.790 MP/s
558 non-palette 3.7607/0.797 MP/s 3.7607/0.816 MP/s
Change-Id: If4041a9c18f7e972f49fcbab8c3e2f013d8bf1cf
Updated VP8LGetBackwardReferences and HashChainFindCopy method with following:
- Remove the recursive CostModelBuild.
- Reuse the lz77 backward refs in CostModelBuild, instead of evaluating it
again (as it was done for recursion_level=0).
- Consolidated the Match-length logic inside FindMatchLength method.
- Removed the logic for altering best_length/val based on the 2D distance.
The additional 162 value (+= 9 * 9 + 9 * 9 - y * y - x * x) can't change the
best_val eval computation to choose a different curr_length, as best_val was
set to 'curr_length << 16'.
Following is the impact on the compression speed/density at default & max
quality, overall this speeds up compression by 5-15% (q=100 -> 75) with a tad
drop (0.02-0.03%) in compression density for the non-palette images.
Before After
bpp/Rate(MP/s) bpp/Rate(MP/s)
q=75 (def)
All 1000 2.4492/1.049 MP/s 2.4498/1.230 MP/s
Palette 0.2719/5.060 MP/s 0.2719/6.110 MP/s
non-Palette 3.7597/0.732 MP/s 3.7607/0.840 MP/s
q=100
All 1000 2.4134/0.125 MP/s 2.4142/0.131 MP/s
Palette 0.2692/2.585 MP/s 0.2692/2.885 MP/s
non-Palette 3.7040/0.079 MP/s 3.7053/0.083 MP/s
Change-Id: I27a5eff3356d876c3e949fd32262244b25678b7a
Compared to previous mode it gives another 10-30% improvement in compression keeping comparable PSNR on corresponding quality settings.
Still protected by the WEBP_EXPERIMENTAL_FEATURES flag.
Change-Id: I4821815b9a508f4f38c98821acaddb74c73c60ac
Evaluate if for Palette images (num_colors <= 256), non-palette
compression path (Subtract green, predictor transform etc) yield an
optimal compression density.
This change reduces the WebP file (for palette images) size by 0.4% with
drop of 3-5% in compression speed.
Change-Id: I1ad66fa94db4fd7ba7bc215763791ef662cd4f42
the number of segments are previously validated, but an explicit check
is needed to avoid a warning under gcc-4.9
Change-Id: Ifa7c0dd7f3f075b3860fa8ec176d2c98ff54fcea
We compact the palette by weighted distance, favoring the green channel.
Average gain on paletted file is ~0.5%, with gain up to 6-7% on some favorable cases.
Encoding speed is unaffected.
Disabled for alpha (or any single-channel input)
Also: always use quality=20 for EncodePalette() since it
doesn't make any real difference.
Change-Id: I19fb14316a366f139a941b45aef5663a33c905e1
SSE2 version is 2.1x faster
This is used to transfer the alpha plane to green channel before lossless compression.
Change-Id: I01d9df0051c183b1ff5d6eb69961d4f43e33141a
Don't combine the Histograms that have trivial (single valued A, R & B)
symbols.
Following is the compression savings data along with compression time (before
& after) per image.
Before After
bpp, rate(MP/s) bpp, rate(MP/s)
Q=25, method = 4 2.508, 1.807 2.499, 1.916
Q=50, method = 4 2.460, 1.488 2.456, 1.512
Q=75, method = 4 2.452, 1.078 2.450, 1.092
Q=25, method = 5 2.505, 1.398 2.496, 1.383
Q=50, method = 5 2.458, 1.170 2.453, 1.143
Q=75, method = 5 2.453, 0.886 2.450, 0.855
This change provides 0.1-0.4% compression gains and speeds up the lossless
compression for the default method=4 (the drop in compression speed is between 1-3.5% for method=5).
Change-Id: Idfd88c2092f37afacd26a97097b3053f8183953a
Tested on 1000 pngs corpus with quality 90-100 it gives ~0.15% improvement
in compression density and ~7% speed up.
Change-Id: I460f56c96707edb3c1f0b51a024e5122e10458df
if ALPHA_LOSSLESS_COMPRESSION produces a too big file (very rare!),
we fall-back to no-compression automatically.
Change-Id: I5f3f509c635ce43a5e7c23f5d0f0c8329a5f24b7
rightmost pixel was missing a copy, which could lead to invalid read.
Also added a lower dimension of 4, below which we use the regular conversion.
This is to prevent corner cases, in addition to not being overkill.
Change-Id: Iac12e7a3d74590f12fe8eeb1830b9891e61439f6
with a special case for dithering==0., it gets somewhat faster on x86
thanks to inlining.
Also, less macros.
Change-Id: Ic2f2bf6718310743bb40cef2104fa759a073e6d5
New function: WebPPictureSmartARGBToYUVA()
This implement smart RGB->YUV conversion.
This is rather undocumented for now, and is triggered using '-pre 4'
preprocessing option.
This is slow-ish and use quite some memory, but should be improvable.
This is somehow a usable beta version.
Change-Id: Ia50a8c30134e4cab8a7d3eb70aef13ce1f6187a1
This compresses the uimage using lossless compression and controlable
decimating pre-process.
Code is under WEBP_EXPERIMENTAL_FEATURE while it's being experimented with.
Change-Id: I8b7f4cfcc3c6afc52a556102842bdbb045ed5ee8
(typecast uint32 pointer to uint64).
The proposed change is little (0.05%) slower but avoids uint32 to uint64
pointer conversion.
Change-Id: I6b8828077ea1324fabd04bfa7e7439e324776250
Sometimes, the error-code was not set correctly.
We now return OUT_OF_MEMORY everytimes it's appropriate
(tested using MALLOC_FAIL_AT mechanism)
Took the opportunity to clean-up the code and dust the error
code returned (some were erroneously set to INVALID_CONFIGURATION)
Change-Id: I56f7331e2447557b3dd038e245daace4fc82214c
only 1 of <lib>_CPPFLAGS and AM_CPPFLAGS is used, with the former
getting precedence when it's defined. configure's DEFAULT_INCLUDES is
covering what's necessary given the include paths are all source
relative.
Change-Id: I7d14076acd266b28a88a3d92bcc3d7165284d5f3
this change has the side-effect of using directory names in the
include, silencing a lint warning.
Change-Id: Ib91cf63a90534e32fadfa5c2372bfdb29f854d02
if res->first = 1, coeffs[0]=0 because of quant.c:749 and line
added at quant.c:744
So, no need for the extra case.
Going forward, TrellisQuantizeBlock() should also be calling
a variant of VP8SetResidualCoeffs() to set the 'last' field.
also: fixes a warning for win64
+ slight speed-up
Change-Id: Ib24b611f7396d24aeb5b56dc74d5c39160f048f0
The luminance needs to be pre- and post- multiplied by
the alpha value in case of rescaling, for proper averaging.
Also:
- removed util/alpha_processing and moved it to dsp/
- removed WebPInitPremultiply() which was mostly useless
and merged it with the new function WebPInitAlphaProcessing()
Change-Id: If089cefd4ec53f6880a791c476fb1c7f7c5a8e60
also changed the token-page layout a little bit to remove
a not-needed field.
This reduces the number of malloc()/free() calls substantially
with minimal increase in memory consumption (~2%).
For the tail of large sources, the number of malloc calls goes
typically from ~10000 to ~100 (e.g.: bryce_big.jpg: 22711 -> 105)
Change-Id: Ib847f41e618ed8c303d26b76da982fbc48de45b9
