Even at high quality setting, the U/V quantizer step is limited
to 4 which can lead to banding on gradient.
This option allows to selectively apply some randomness to
potentially flattened-out U/V blocks and attenuate the banding.
This option is off by default in 'dwebp', but set to -dither 50
by default in 'vwebp'.
Note: depending on the number of blocks selectively dithered,
we can have up to a 10% slow-down in decoding speed it seems.
Change-Id: Icc2446007f33ddacb60b3a80a9e63f2d5ad162de
Earlier we were only testing for bit_pos == LBITS. But this is not
sufficient,
as bit_pos can jump from < LBITS to > LBITS.
This was resulting in some bit-stream truncation errors not being
caught.
Note: Not a security bug though, as br->pos wasn't incremented in such
cases
and so we weren't reading beyond the buffer.
Change-Id: Idadcdcbc6a5713f8fac3470f907fa37a63074836
in_bits is const. Trying to apply bswap on it, one gets the error message:
error: read-only variable 'in_bits' used as 'asm' output
Change-Id: I0bef494b822c83d8ea87b1938b0e486d94de4742
speeds up those codes that are not part of the main lookup.
This gives a 10 % speedup for a photographic image.
Change-Id: Ief54b0ad77db790a01314402ad351b40ac9a7be4
rather than symlink the webm/vpx terms, use the same header as libvpx to
reference in-tree files
based on the discussion in:
https://codereview.chromium.org/12771026/
Change-Id: Ia3067ecddefaa7ee01550136e00f7b3f086d4af4
subdirectories with more than one target can have the install targets
run in parallel with make -jN. group the shared headers in one place to
produce a common install target.
Change-Id: I1f3aa338a8ee6d681de1e5d0b2c6244d2c3d5451
-> split libraries further into decoder / encoder
-> add libwebpdecoder.a in Makefile.unix
-> make dwebp link against libwebpdecoder.a in Makefile.unix
also: in makefile.unix, pass EXTRA_FLAGS to LDFLAGS too
(otherwise, -m32 wouldn't work, e.g.)
Change-Id: Ief3da02a729dd86bbaf949ed048836716941657f
Simplify and re-organize the VP8L bit-reader functions
(e.g.: the 40-bit look-ahead code was helping much)
Speed-up with LBITS=64, on arm7-a:
=> before:
./dwebp_justify_24_neon -v bryce_ll.webp
Time to decode picture: 11.393s
File bryce_ll.webp can be decoded (dimensions: 11158 x 2156).
...
=> after (LBITS=64): Time to decode picture: 9.953s
making the VP8L bit-reader in 32 bit mode is going to be
harder (because we need to be able to read two symbols
at a time, each with max length 15 bits)
Change-Id: I89746fb103b87b5e2fd40a3208a6fbc584b88297
This flag will make the code use no uint64, no asm, and no fancy
trick, but instead aim at being as simple and straightforward as
possible.
Main use is to help emscripten generate proper JS code.
More code needs to be simplified later.
Also: tune the BITS values to be 24 and make use of WEBP_RIGHT_JUSTIFY
Here are the typical timing for decoding a large image:
ARM7-a:
dwebp_justify_32_neon Time to decode picture: 3.280s
dwebp_justify_24_neon Time to decode picture: 2.640s
dwebp_justify_16_neon Time to decode picture: 2.723s
dwebp_justify_8_neon Time to decode picture: 2.802s
dwebp_justify_32 Time to decode picture: 4.264s
dwebp_justify_24 Time to decode picture: 3.696s
dwebp_justify_16 Time to decode picture: 3.779s
dwebp_justify_8 Time to decode picture: 3.834s
dwebp_32_neon Time to decode picture: 4.010s
dwebp_24_neon Time to decode picture: 2.725s
dwebp_16_neon Time to decode picture: 2.852s
dwebp_8_neon Time to decode picture: 2.778s
dwebp_32 Time to decode picture: 4.587s
dwebp_24 Time to decode picture: 3.800s
dwebp_16 Time to decode picture: 3.902s
dwebp_8 Time to decode picture: 3.815s
REFERENCE (HEAD) Time to decode picture: 3.818s
x86_64:
dwebp_justify_32 Time to decode picture: 0.473s
dwebp_justify_24 Time to decode picture: 0.434s
dwebp_justify_16 Time to decode picture: 0.450s
dwebp_justify_8 Time to decode picture: 0.467s
dwebp_32 Time to decode picture: 0.474s
dwebp_24 Time to decode picture: 0.468s
dwebp_16 Time to decode picture: 0.468s
dwebp_8 Time to decode picture: 0.481s
REFERENCE (HEAD) Time to decode picture: 0.436s
i386:
dwebp_justify_32 Time to decode picture: 0.723s
dwebp_justify_24 Time to decode picture: 0.618s
dwebp_justify_16 Time to decode picture: 0.626s
dwebp_justify_8 Time to decode picture: 0.651s
dwebp_32 Time to decode picture: 0.744s
dwebp_24 Time to decode picture: 0.627s
dwebp_16 Time to decode picture: 0.642s
dwebp_8 Time to decode picture: 0.642s
Change-Id: Ie56c7235733a24f94fbfc2e4351aae36ec39c225
When the config option '--enable-libwebpdecoder' is specified, the
lean decoder library 'libwebpdecoder' will be created in addition to
libwebp. Also dwebp binary will be linked to libwebpdecoder, if this
config option is specified.
Change-Id: I9de3e149b59c9a8390fae2ba660941749640e54a
Actually, it turns out we now should never call these functions
with a zero size, otherwise something is wrong in the logic.
Change-Id: Ie414fcbec95486c169190470a71f2cff0843782a
also change lossless encoder logic, which was relying on explicit
NULL return from WebPSafeMalloc(0)
renamed function to CheckSizeArgumentsOverflow() explicitly
addresses issue #138
Change-Id: Ibbd51cc0281e60e86dfd4c5496274399e4c0f7f3
The main advantage is that you can avoid the use of uint64_t
some times, sticking to 32bit only.
Default still is BITS=32, this is mainly "in case".
Change-Id: Id694028793117ba822c37d46ef6c52fa0afed4ac
- Separate out mux.h and demux.h
- muxtypes.h: new header for data types common to mux/demux
- Move some misc read/write utilities to utils/utils.h
- Remove some duplicate methods.
- Separate out mux/demux libraries
Change-Id: If9b9569b10d55d922ad9317ef51710544315d6de
Returning 0 (equal) can lead to undefined behaviour.
And, in our cases we'll never have equal keys (added asserts for that)
Change-Id: Ifaf202df321d3f877ad2a03de42e0d6cdd1b2388
