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
We add the following MSA optimized encoder quantization functions:
- QuantizeBlock
- Quantize2Blocks
Change-Id: Ie32b442afa99eee62d2ef48942b41116a4e157d3
pre-allocating a sorted[] array for most common cases of small
alphabet size cuts a lot of traffic.
Change-Id: I73ff2f6e507f81b0b0bb7d9801a344aa4bcb038a
+ s/src_a/dst_a/
+ remove unnecessary (void) as expected_num_lines_out is used within the
function
Change-Id: Ic45f798ef22bd19eaabf1a0512d1cf8a201bb4b5
- 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
We add the following MSA optimized color transform functions:
- AddGreenToBlueAndRed
- TransformColorInverse
Change-Id: Iceab3813905955aa8b811253df9188512fc7de3f
(in case no alpha was present in the source .webp,
but user requested some)
Change-Id: I9011d38237907c60d6796a86bd2c72166aa80f27
(cherry picked from commit 06a38c7b1c)
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
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 function can be called not to decode pixels, but simply
to finish processing (through process_func()) the already decoded
pixels.
Change-Id: I80485e92e3c47f0aa3389476dcb82745a243fc4a
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
On the non-fast path (use_8b_decode_=0) for decoding the alpha-mask,
we could end up requesting ApplyInverseTransform() with more rows
to process than NUM_ARGB_CACHE_ROWS. This could only happen on the
very last bottom rows of the image.
* ProcessRows() doesn't need to be fixed, since we never request more
than NUM_ARGB_CACHE_ROWS rows. Added an assert for that.
* the use_8b_decode_=1 case doesn't use argb_cache_, but rather does
the palette-decoding call directly. So, no problem here too.
Only the generic (and rather rare) case of calling ExtractAlphaRows()
was affected.
Change-Id: I58e28d590dcc08c24d237429b79614abcef1db7c
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
In case where the same offset is found in consecutive pixels,
the cost computation from one pixel can be re-used for the next.
Change-Id: Ic03c7d4ab95f3612eafc703349cfefd75273c3d7
and also recycle the malloc'd intervals
This avoids quite some malloc/free cycles during interval managment.
Change-Id: Ic2892e7c0260d0fca0e455d4728f261fb4c3800e
In a lot of cases, only one interval is used. This can cause
a lot of malloc/free cycles for only 56 bytes. By caching this
single interval and re-using it, we remove this cycle in most
frequent cases.
Change-Id: Ia22d583f60ae438c216612062316b20ecb34f029
As per the spec
(https://developers.google.com/speed/webp/docs/riff_container), only the
extended file format can contain an unknown chunk. So, when assembling a
WebP file with muxer, whenever there is an unknown chunk present, we
should create a VP8X chunk (even though none of the features are
present).
BUG=webp:294
Change-Id: I5da52d311e1853d40063d0f5026100d4325effaa
In some cases, the hash chain for a function is filled several
times:
- GetBackwardReferences -> CalculateBestCacheSize ->
BackwardReferencesLz77 that computes the hash chain
- GetBackwardReferences ->
(not always) BackwardReferencesTraceBackwards ->
BackwardReferencesHashChainDistanceOnly that computes the hash
chain in a slightly different way
Speed and compression performance are slightly changed (+ or -)
but will be homogneized in a later patch.
Change-Id: I43f0ecc7a9312c2ed6cdba1c0fabc6c5ad91c953
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
tl;dr
We do the following:
- Start with transparent value of 0x00000000 instead of 0x00ffffff, so that
WebPCleanupTransparentAreaLossless() is a no-op.
- Restore the original canvas after lossy encoding, to discard changes made by
WebPCleanupTransparentArea() before the next encode.
Explanation of why:
In the mixed mode, anim_encoder tries to encode using both lossless and lossy
compression. In fact, when "min_size" option is enabled, there are at most 4
encodes that can happen in this order:
- lossless with dispose none
- lossy with dispose none
- lossless with dispose background
- lossy with dispose background
But both lossless and lossy both potentially modify the canvas during encode
(for better compression):
- Lossless: WebPCleanupTransparentAreaLossless() turns all transparent pixels
to 0x00000000
- Lossy: WebPCleanupTransparentArea() flattens some transparent pixels
So, the result is that, sometimes we feed the modified canvas to the encoder
instead of the original one, which isn't the right thing to do.
This also applies to just lossless or just lossy encoding, as multiple encodes
happen (with the two dispose methods) in those cases too.
Change-Id: Idfa8ce831a1627014785ba7d0316c42f72594455
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
Instead of comparing all the following pixels over len (which can
frequently reach the maximum MAX_LENGTH=4096 for some images),
intervals are stored and compared.
Change-Id: I0dafef6cc988dde3c1c03ae07305ac48901d60ee
The old implementation in enc/near_lossless.c performing a separate
preprocessing step is used only when a prediction filter is not used,
otherwise a new implementation integrated into lossless_enc.c is used.
It retains the same logic for converting near lossless quality into max
number of bits dropped, and for adjusting the number of bits based on
the smoothness of the image at a given pixel. As before, borders are not
changed.
Then, instead of quantizing raw component values, the residual after
subtract green and after prediction is quantized according to the
resulting number of bits, taking care to not cross the boundary between
255 and 0 after decoding. Ties are resolved by moving closer to the
prediction instead of by bankers’ rounding.
This results in about 15% size decrease for the same quality.
Change-Id: If3e9c388158c2e3e75ef88876703f40b932f671f
copy and paste error in the previous commit, change
no_sanitize("unsigned-integer-overflow") from WEBP_UBSAN_IGNORE_UNDEF ->
WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW
Change-Id: Id178ee14df1f2c4923a91ce423241e26b60b5d32
add WEBP_UBSAN_IGNORE_UNDEF to WebPMemToUint32() / WebPUint32ToMem()
when WEBP_FORCE_ALIGNED is unset
Change-Id: I726b2e708ce29681584eb10c8874d5cf1e798756
