moves the implementation to ParseHeadersInternal. this also allows
decoding to start at a VP8X sub-chunk, e.g. 'ALPH'.
Change-Id: I06791f87d90f888de32746ecb02705e4b0ff227a
ParseVP8X was checking for presence of extra 20 bytes (after RIFF header).
This check should not be executed for non-mux (non-VP8X) images.
Change-Id: I3fc89fa098ac0a53102e7bbf6c291269817c8e47
Ensure that the lossless bit-stream doesn't allow for such cases and
safe-gaurd decoder against indefinite recursion.
Change-Id: Ia6d7f519291de8739f79a977a5800982872aae71
The new modes are
MODE_rgbA
MODE_bgrA
MODE_Argb
MODE_rgbA_4444
It's binary incompatible, since the enums changed.
While at it, i removed the now unneeded KeepAlpha methods.
-> Saved ~12k of code!
* made explicit mention that alpha_plane is persistent,
so we have access to the full alpha plane data at all time.
Incremental decoding of alpha was planned for, but not
implemented. So better not dragged this constaint for now
and make the code easier until we revisit that.
Change-Id: Idaba281a6ca819965ca062d1c23329f36d90c7ff
Change the lossless signature to 0x2f
Add 1 bit indicator for 'droppable (or trivial) alpha)'.
Add 3 bit lossless version (for future extension like yuv support).
Change the sub-resolution information to 3 bits implying range [2 .. 9]
Change-Id: Ic7b8c069240bbcd326cf5d5d4cd2dde8667851e2
Previously, it used to assume any raw bitstream is a VP8 one.
Also,
- Factor out VP8CheckSignature() & VP8LCheckSignature().
- Use a local var for *data_ptr in ParseVP8Header() for
readability.
Change-Id: I0fa8aa177dad7865e00c8898f7e7ce76a9db19d5
frame's InitIo should not reset fancy_upsampling flag.
This flag (fancy_upsampling) is set via CustomSetup -> WebPIoInitFromOptions
and frame's InitIo() is resetting it to 0.
Change-Id: I64b54cdfba43799c0a5aa8e384575af5d6331674
may be useful later for instance to bypass some code
if we know we don't use the Bundle+ColorMap transform.
Change-Id: I9dc70d18165b2363ad9ede763684ef3d8eba5903
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
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
* 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
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
[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
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
* 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
src/dec/Makefile.am: add missing reference to vp8li.h
src/{dec,dsp,enc}/Makefile.am: move some headers to noinst_
Change-Id: I0e2bc69980bd8175d99ad0ab63f537ef9e425b77
- use common file organization across subdir makefiles
- append lib/source/header list variables and sort
Change-Id: I0653e1c73a4552b0c43d21f321b22b4972d6e87b
* each with their own decoder instances.
* Refactor the incremental buffer-update code a lot.
* remove br_offset_ for VP8LDecoder along the way
* make VP8GetHeaders() be used only for VP8, not VP8L bitstream
* remove VP8LInitDecoder()
* rename VP8LBitReaderResize() to VP8LBitReaderSetBuffer()
(cherry picked from commit 5529a2e6d47212a721ca4ab003215f97bd88ebb4)
Change-Id: I58f0b8abe1ef31c8b0e1a6175d2d86b863793ead
