- Make sure alpha flag is set in case of a lossless file with VP8X chunk.
The semantic of ALPHA_FLAG changes with this: it means the images
contain alpha (rather than ALPH chunk in particular).
- Update the mux container spec to add 1-line description of alpha
flag.
- Rename "HasLosslessImages()" to "MuxHasLosslessImages()", and other
similar function renames.
- Rename FeatureFlags to WebPFeatureFlags
- Elaborated a comment for a special case.
- A misc comment fix.
Change-Id: If212ccf4338c125b4c71c10bf281a51b3ba7ff45
Defining LOCAL_ARM_NEON = true can result in neon instructions being
used in portions unprotected by the cpu check.
This changes defines a WEBP_USE_NEON/WEBP_ANDROID_NEON pair similar to
the SSE2 code and MSVC.
Change-Id: Ifac010b06e42c73d5aca529baa2198c6796674bd
This saves ~26 bytes of headers.
* introduce new VP8LDecodeAlphaImageStream() for decoding
* use VP8LEncodeStream() for encoding
* refactor code a bit
still TODO: make the alpha-quality/enc-method user-configurable
Change-Id: I23e599bebe335cfb5868e746e076c3358ef12e71
Limit the overall number of transformations to 4 and disallow any
duplicate transform for decoding an image.
Change-Id: Ic4b0ecd553db96702e117fd073617237d95e45c0
this allows later customization of data output method.
No perf diff observed, even if ProcessRows is no longer inlined.
Change-Id: I6933a3612a9cf6c108cf2776dfde0ae80c6c07c0
+ small opportunistic fixes:
* allow NULL decoded_data to be passed to DecodeStream
and clarity (with assert()) when to do so
* AllocateAndInitRescaler() was already setting error status,
as it should. No need to do it at caller's site
Change-Id: I30867e596564a7f459a0d1ddbf6f5d312414b7fd
* RIFF header is omitted
* rename NewVP8LEncoder and DeleteVP8Encoder
* change the signature to take a "const WebPPicture*"
(it was non-const just because we were setting some error potentially)
* made the pic_ field const in VP8LEncoder too.
* trap the bitwriter::error_ too
* simplify some signatures to take WebPPicture* instead
of unneeded VP8LEncoder*
VP8LEncodeStream() will be called directly to compress alpha channel
header-less.
Change-Id: Ibceef63d2b3fbc412f0dffc38dc05c2dee6b6bbf
This is a border-case situation: the picture is not const, because
we're change its error status. But taking it non-const forces
the caller to carry a non-const picture all around the code just
in case (0.00001% of the time?) something bad happen.
This pretty much the same as making all objects non-const because
we'll eventually call delete or free() on them, which is quite a
non-const operation. Well... Better allow constness enforcement for
the remaining 99.9999% of the code.
Change-Id: I9b93892a189a50feaec1a3a518ebf488eb6ff22f
now, we only use 2 bits for the filtering method, and 2 bits
for the compression method.
There's two additional bits which are INFORMATIVE, to specify
whether the source has been pre-processed (level reduction)
during compression. This can be used at decompression time
for some post-processing (see DequantizeLevels()).
New relevant spec excerpt:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ChunkHeader('ALPH') |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Rsv| P | F | C | Alpha Bitstream... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Compression method (C): 2 bits
: The compression method used:
* `0`: No compression.
* `1`: Backward reference counts encoded with arithmetic encoder.
Filtering method (F): 2 bits
: The filtering method used:
* `0`: None.
* `1`: Horizontal filter.
* `2`: Vertical filter.
* `3`: Gradient filter.
Pre-processing (P): 2 bits
: These INFORMATIVE bits are used to signal the pre-processing that has
been performed during compression. The decoder can use this information to
e.g. dither the values or smooth the gradients prior to display.
* `0`: no pre-processing
* `1`: level reduction
Decoders are not required to use this information in any specified way.
Reserved (Rsv): 2 bits
: SHOULD be `0`.
Alpha bitstream: _Chunk Size_ - `1` bytes
: Encoded alpha bitstream.
This optional chunk contains encoded alpha data for a single tile.
Either **ALL or NONE** of the tiles must contain this chunk.
The alpha channel data is losslessly stored as raw data (when
compression method is '0') or compressed using the lossless format
(when the compression method is '1').
Change-Id: Ied8f5fb922707a953e6a2b601c69c73e552dda6b
will be called by alpha post-processing, although doing nothing for now.
Gradient smoothing would be nice-to-have here. Patch welcome!
Change-Id: I534cde866bdc75da22d0f0a6d1373c90e21366f3
* Method #1 is now calling the lossless encoder on the alpha plane.
Format is not final, it's just a first draft. We need ad-hoc functions.
* removed now useless utils/alpha.*
* added utils/quant_levels.h instead
* removed the TCoder code altogether
Change-Id: I636840b6129a43171b74860e0a0fc5bb1bcffc6a
- Separate out 'CHUNK_INDEX' from 'TAG_ID' (this is to help with the
situation where two different tags - "VP8 " and "VP8L" can have the
same TAG_ID -> IMAGE_ID).
- Some internal methods now take 'CHUNK_INDEX' param instea of 'TAG_ID'
as appropriate.
- Add kChunks[] entry for lossless.
- Rename WebPMuxImage.vp8_ --> WebPMuxImage.img_
- SetImage() and AddFrame/Tile() infer whether the bitstream is a
lossless one based on LOSSLESS_MAGIC_BYTE. The correct tag is stored
based on this.
Also, handle the case when GetVP8Info/GetVP8LInfo() fails.
Change-Id: I6b3bc9555cedb791b43f743b5a7770958864bb05
-> lot of simplifications ensue and we should be able to get rid of
ClearHuffmanTreeIfOnlyOneSymbol() too, in a subsequent patch.
Change-Id: Ic4c51d05e4b1970e37f94ffd85fae6a02e4a6422
Allocate big chunk of memory in GetHuffBitLengthsAndCodes, instead of allocating in a loop.
Also fixed the potential memleak.
Change-Id: Idc23ffa306f76100217304444191a8d2fef9c44a
The size written in VP8L header should be without padding.
(Also clarified this code using consts).
Change-Id: Ic6583d760c0f52ef61924ab0330c65c668a12fdc
When we are at end-of-stream, but haven't decoded all pixels, we should
return an error.
Also remove an obsolete TODO.
Change-Id: I3fb1646136e706da536d537a54d1fa487a890630
- Symbols added to the tree are valid inside HuffmanTreeBuildExplicit().
- In HuffmanTreeBuildImplicit(), make sure 'root_symbol' is
valid in case of a single symbol tree.
Change-Id: I7de5de71ff28f41e2d6228b29ed8dd4a20813e99
if histogram_image_size is reduced in when writing the histogram_image
the bit arrays would leak any remaining elements. store their element
count separately.
Change-Id: I710142a11ebd4325faec7bd65c2d2572aae19307
[Basically, the condition "src - dist < data" can be wrongly evaluated
to be false if "src < dist" due to underflow. Instead, "src - data <
dist" is the correct condition, as "src > data" is always true and so
there would never be an underflow].
Change-Id: Ic9f64bfe76a9acae97abc1fb7c1f4868e81f1eb8
CompareHuffmanTrees() and SetBitDepths()):
- Move 'tree_size' initialization and malloc for 'tree + tree_pool'
outside the loop.
- Some renames/tweaks for readability.
Change-Id: I5cb3cc942afac6e9f51a0b97c57ee897677a48a2
The current implementation doesn't take care one byte
signature and associated one byte padding (for odd sized chunk).
Change-Id: I35b81d0644818cdba38189aa48c75db5f92e68f4
The new method VP8LGetBackwardReferences hides internal
heuristics used for choosing RLE or LZ77 based refs.
- Tuned VP8LHashChainFindCopy for better compression at higher Q.
- Refactored code.
- Removed the unused method VP8LVerifyBackwardReferences.
Change-Id: Ibb7bb072bab5a49a001577a20d88226f52e6c663
arrays can be passed directly as only their members are being modified.
this also reduces the allocation for bit_codes[] by taking the
sizeof(type)=2 rather than sizeof(ptr)=4/8 in one case.
Change-Id: Idad20cead58c218b58d90b71699374fefd01cad9
add proper cpu-detection for Android targets
Fixes issue #118 (and is a better solution for #117).
based on patch by pepijn vaneeckhoudt
Change-Id: I6b00ea6d51ca658ccf6a3d55b87b99c01c6805be
* lossless_encoder: (46 commits)
split StoreHuffmanCode() into smaller functions
more consolidation: introduce VP8LHistogramSet
big code clean-up and refactoring and optimization
Some cosmetics in histogram.c
Approximate FastLog between value range [256, 8192]
Forgot to update out_bit_costs to symbol_bit_costs at one instance.
Evaluate output cluster's bit_costs once in HistogramRefine.
Simple Huffman code changes.
Lossless decoder: remove an unneeded param in ReadHuffmanCodeLengths().
Reducing emerging palette size from 11 to 9 bits.
Move GetHistImageSymbols to histogram.c
Improve predict vs no-predict heuristic.
code-moving and clean-up
reduce memory usage by allocating only one histo
Restrict histo_bits to ensure histo_image size is under 32MB
further simplification for the meta-Huffman coding
A quick pass of cleanup in backward reference code
Make transform bits a function of encode method (-m).
introduce -lossless option, protected by USE_LOSSLESS_ENCODER
Run TraceBackwards for higher qualities.
...
Conflicts:
src/enc/webpenc.c
Change-Id: I9a5d98cba0889ea91d10699466939cc283da345a
VP8LHistogramSet is container for pointers to histograms that
we can shuffle around. Allocation is one big chunk of memory.
Downside is that we don't de-allocate memory on-the-go during
HistogramRefine().
+ renamed HistogramRefine() into HistogramRemap(), so we don't
confuse with "HistogramCombine"
+ made VP8LHistogramClear() static.
Change-Id: Idf1a748a871c3b942cca5c8050072ccd82c7511d
* de-inline some function
* make VP8LBackwardRefs be more like a vectorwith max capacity
* add bit_cost_ field to VP8LHistogram
* general code simplifications
* remove some memmov() from HistogramRefine
* simplify HistogramDistance()
...
Change-Id: I16904d9fa2380e1cf4a3fdddf56ed1fcadfa25dc
Profiled data: Profiled few images and found that in the function VP8LFastLog,
90% of time table lookup is performed, while rest of time (10%) call to log
function is made. Typical lookup accounts for 10 CPU instructions and call to
log 200 instruction counts. The weighted average comes out to be 30
instructions per call. For mid qualities (25-75), this function (VP8LFastLog)
accounts for 30-50% of total CPU cycles (via call path: VP8LCOlorSpaceTransform
-> PredictionCostCrossColor -> ShannonEntropy). After this change, the log is
called less that 1% of time, with average instructions being 15 per call.
Measured the performance over 1000 files for various qualities and found
overall compression speedup between 10-15% (in quality range [0, 75]). The
compression density loss is around 0.5% (though at some qualities, compression
is little better as well).
Change-Id: I247bc6a8d4351819c871f19d65455dc23aea8650
Avoid bit_costs evaluated every time in function HistogramDistance. Also moved
VP8LInitBackwardRefs and VP8LClearBackwardRefs to backward_references.h
Change-Id: Id507f164d0fc64480aebc4a3ea3e6950ed377a60
No empty trees are codified with the simple Huffman code. The simple Huffman
code is simplified to be either a 1-bit code or 8-bit code for symbols.
Change-Id: I3e2813027b5a643862729339303d80197c497aff
This improves compression density. For example, at quality 95 on 1000 PNGs:
bpp(before) = 2.447 and bpp(after) = 2.412
Change-Id: I19c343ba05cca48a6940293721066502a5c3d693
* removed use_lz77_ field, and added cache_bits_ one.
* use more BackwardRefs params
* move code around to organize more logically
* reduce memory use on histo
...
Change-Id: I833217a1b950189cf486704049e3fe28382ce335
instead of lz77+rle
* introduce VP8LBackwardRefs structure and simplify the code by not passing
around {PixOrCopy/int} pairs.
More functions should be turned into using this struct (TODO(later)).
Change-Id: I69c5c9fa61dddd61a2abc2824d70b8606a1c55b6
* don't transmit the number of Huffman tree group explicitly
* move color-cache information before the meta-Huffman block
* also add a check that color_cache_bits is in [1..11] range, as per spec.
Change-Id: I81d7711068653b509cdbc1151d93e229c4254580
(Essentially, there was no need of a separate 'argb_palette' array. And
argb_palette[0] was never being set).
Change-Id: Id0a8c7e063d3af41e39fc9b8661611b51ccc55cd
make elements of "Multiplier" struct unsigned, so that any negative values are
automatically converted to "mod 256" values.
Change-Id: Iab4f9bacc50dcd94a557944727d9338dbb0982f7
so that it uses original values of left, top etc for prediction rather than the
predicted values of the same. Also, do some renaming in the same to make it
more readable.
Change-Id: I2fe94e35a6700bd437f5c601e2af12323bf32445
