It was a bad implementation of a Lehmer random number generator
(the saturation was done wrong and mostly & was used instead of % .....).
That lead to "for" loop stuck with the same values given a specific seed,
hence wasted "for" loops (e.g. seed getting at 374988608 and modulo of 64
later leads to 0 even when updating the seed with the old formula).
As the "for" loops now always return a proper pair of histograms, their
number can greatly be reduced, hence a speedup.
Change-Id: I9f5b44d66cc96fd4824189d92276c3756c8ead5b
This code is ultra-critical for lossless decoding, especially on ARM.
The extra call VP8LIsEndOfStream() was causing unnecessary slow-down.
Now, we check for bitstream-end separately in the main loop.
Change-Id: I739b5d74cc29578e2b712ba99b544fd995ef0e0d
Currently, none are available. If WEBP_HAVE_SSE2 eventually works,
we'll have to refine this conditionals.
BUG=webp:261
Change-Id: Ibc63ee1c013f2a4169eeb85cc8b6317b6420c2ad
The build is based on CMake.
There is a demo HTML page under webp_js/index.html
See README.webp_js file.
BUG=webp:261
Change-Id: I6612378b89907efd7b863720c6becf98385fc406
Previously, the stochastic method for histogram
combination could finish in a greedy way
if the number of iterations to perform so was smaller.
Except that another greedy combination was performed
afterwards ... hence wasted CPU in some cases.
Change-Id: Ic0f26873e6dc746679486b91cb35d73efee91931
The initial re-writing of this part of the code with intervals
had to be done with a complex logic (mostly intervals with a
lower and upper bound, not a constant value like now) to properly
deal with the inefficiencies of the then LZ77 algorithm.
The improvements made to LZ77 since, now allow for a simpler logic.
There were also small errors in the interval insertion logic
that lead to small inefficiencies (hence a slightly better
compression rate).
Change-Id: If079a0cafaae7be8e3f253485d9015a7177cf973
Other libraries are also cleaned to automatically read the Makefile.am.
Dependencies also got cleaned.
Change-Id: I5d1ff0a4010d59e8c929ed0c9c30c05d83c271f8
Uses WebPToSDL() generic function defined in vwebp_sdl.[ch].
This function is not included in the libextras library, because it
would bring in an SDL dependency. Probably too heavy for now.
WebPToSDL() is separate, because it will be called used by the javascript
version of libwebp (through emscripten build rules)
Change-Id: Ic85b36f8ce4784f46023656278f6480be6802834
previously this was reading the first file a second time, since:
b0450139 ReadImage(): restore size reporting
BUG=webp:329
Change-Id: Ie75192e36a06102b7617841768a18d4dfb02d1f5
drop './' from the reference in webp_quality_LDADD.. this form is used
in the other makefiles. this fixes a parallel build failure seen under
freebsd:
make[1]: don't know how to make ./libwebpextras.la. Stop
Change-Id: I59635a0c747d402cd990f6379eb1948c3e40f278
Documentation says: "if kmin == 0, then key-frame insertion is disabled;
and if kmax == 0, then all frames will be key-frames."
Reading this, you'd expect that if kmax == 0, then with any kmin <= 0
all frames will be key-frames. But actually the kmin <= 0 test is caught
first and you get the opposite (no keyframes but the first). You'd have
instead to set kmax == 0 and any value kmin > 0, which is absolutely
counter-intuitive (reversing order).
Moreover kmax == 1 has no valid kmin (kmin == 1 conflicts with the
`kmax > kmin` rule and kmin == 0 conflicts with `kmin >= kmax / 2 + 1`).
So it should be considered an exception too.
Instead I propose this new logic:
- kmax == 1 means that all frames are keyframes (you are explicitly
requesting a keyframe every 1 frame at most, i.e. all frames).
- kmax == 0 means no keyframes (you ask for a keyframe every 0 frames,
i.e. never).
This is more "logical" language-wise, and also does not involve any
conflicts about what if both kmax and kmin are 0, since now a single
property value is meaningful for the 2 exceptional cases.
Change-Id: Ia90fb963bc26904ff078d2e4ef9f74b22b13a0fd
(cherry picked from commit 2dc0bdcaee)
Compile with XCode, it appears quite slower than the C-version,
especially for arm64.
Change-Id: Ic46dba184a36be454fef674129d2f909003788fc
(cherry picked from commit 4f3e3bbd44)
Documentation says: "if kmin == 0, then key-frame insertion is disabled;
and if kmax == 0, then all frames will be key-frames."
Reading this, you'd expect that if kmax == 0, then with any kmin <= 0
all frames will be key-frames. But actually the kmin <= 0 test is caught
first and you get the opposite (no keyframes but the first). You'd have
instead to set kmax == 0 and any value kmin > 0, which is absolutely
counter-intuitive (reversing order).
Moreover kmax == 1 has no valid kmin (kmin == 1 conflicts with the
`kmax > kmin` rule and kmin == 0 conflicts with `kmin >= kmax / 2 + 1`).
So it should be considered an exception too.
Instead I propose this new logic:
- kmax == 1 means that all frames are keyframes (you are explicitly
requesting a keyframe every 1 frame at most, i.e. all frames).
- kmax == 0 means no keyframes (you ask for a keyframe every 0 frames,
i.e. never).
This is more "logical" language-wise, and also does not involve any
conflicts about what if both kmax and kmin are 0, since now a single
property value is meaningful for the 2 exceptional cases.
Change-Id: Ia90fb963bc26904ff078d2e4ef9f74b22b13a0fd
the default is format is roman, fixes:
`R' is a string (producing the registered sign), not a macro.
Change-Id: If2bce714eff1237cd1702ae1143323249d85b93b
