MAX_LEN -> max_len
This was sub-optimal at the end of the picture, when there's
less than MAX_LEN bytes left to match.
Change-Id: I5ebe1fca4e7c112dcd34748a082d1c97f95eb099
often reduces compressed size by ~10's of bytes
+ refactored / sped-up the prediction code (gradient: ~30% faster)
Change-Id: I26bd983655dad4f85d5c5ddc20a1980f384c4dd6
.. where only 2 filtering modes are potentially
tried, instead of all of them. This is fast than the exhaustive 'best'
mode, and not much worse.
Options for cwebp are:
-alpha_filter none
-alpha_filter fast (<- default)
-alpha_filter best (<- slow)
Change-Id: I8cb90ee11b8f981811e013ea4ad5bf72ba3ea7d4
Fix bug for Alpha data in RGBA_4444 color-mode.
The Alpha data is required to be clipped [0, 15] while
converting from 8 bits to 4 bits.
Change-Id: I80705d575c35121beb9633a05ec8823435c79586
Add predictive filtering option for Alpha plane.
Valid range for filter option is [0, 5] corresponding to prediction
methods none, horizontal, vertical, gradient & paeth filter.
The prediction method 5 will try all the prediction methods (0 to 4)
and pick the prediction method that gives best compression.
Change-Id: I9244d4a9c5017501a9696c7cec5045f04c16d49b
- add check for native log2 to configure
- use a common define (NOT_HAVE_LOG2) to enable use of local library
version for non-autoconf platforms without their own version,
currently msvc and android
This uses a negative (NOT_HAVE_) to simplify the ifdef
Change-Id: Id0610eed507f8bb9c5da338918112853d5c8127a
Quite handy and simple (for now).
It's not yet incorporated within the build system (autotools or
makefile.unix), because it gets complicated with OpenGL. TODO(later).
For now, there's some ready-to-use command line for compiling on Linux
or Mac in the header of vwebp.c
Later, this tool will be supplemented with support for animation,
tiling, zooming, etc.
Change-Id: I292972cea4862536afbe8c9ec444c590d152f086
alpha information is not to be found at RIFF chunks level, not
in the VP8 bitstream (that was a tmp hack)
Change-Id: Idd1629c696b03c26f6f30650d7216f627f1761df
This speeds things up for long message, while not damaging
the stats too much for usual-sized cases
Change-Id: I3f45e28b771d701e2e1da11eb800de18c4ed12fc
- Fix the off-by-one diff when cropping with simple-filter.
- Fix a bug in incremental decoding in case of alpha.
- In VP8FinishRow(), do not decode alpha when y_start > y_end.
- Correct output of alpha channel for MODE_ARGB.
- Correct output of alpha channel for MODE_RGBA_4444.
Change-Id: I785763a2a704b973cc742ad93ffbb53699d1fc0a
- Support for adding/getting frames/tiles with alpha in webpmux
- For "-info" option in webpmux binary, add alpha related info
Change-Id: Iccd2fd35ab8453dabd74779f12f2844ab76d0538
Updated cwebp (Webp Encoder) binary to support Alpha encoding.
Modified man page and WebP container spec appropriately.
Change-Id: I52f6a5cb3e870c386591e9a7776293fa6a8fb04b
Extend WebP Encode functionality to encode Alpha data and produce
bit-stream (RIFF+VP8X+ALPH+VP8) corresponding to WebP-Alpha.
Change-Id: I983b4cd97be94a86a8e6d03b3b9c728db851bf48
Extend WebP decode functionality to extract Alpha data (support ALPH
chunk) and decode the Alpha plane using Alpha (utils/alpha) core-lib.
Change-Id: I6f0ee1b189c13caba3c1dd9b681383bfd00aa212
Add code for Alpha encoding & decoding. The alpha compression is done
via backward reference counts encoded with Arithmetic encoder (TCoder).
Also provided is lossy Alpha pre-processing option via level-quantizations
using kNN heuristic.
Change-Id: Ib6b13530c1a4ab6493edcb586ad29fe242bc1766
