Enable the WebP near-lossless feature by pre-processing the image to smoothen
the pixels.
On a 1000 PNG image corpus, for which WebP lossless (default settings) gets
25% compression gains, following is the performance of near-lossless feature
at various '-near_lossless' levels:
-near_lossless 90: 30% (very very high PSNR 54-60dB)
-near_lossless 75: 38% (very high PSNR 48-54dB)
-near_lossless 50: 45% (high PSNR 42-48dB)
-near_lossless 25: 48% (moderate PSNR 36-42dB)
-near_lossless 10: 50% (PSNR 30-36dB)
WebP near-lossless is specifically useful for discrete-tone images like
line-art, icons etc.
Change-Id: I7d12a2c9362ccd076d09710ea05c85fa64664c38
add additional return checks and asserts to avoid:
C6102: Using 'XXX' from failed function call ...
Change-Id: I51f5fa630324e0cd7b2d9fceefecb4f4021474b1
width / height are unsigned; fixes a warning with msvs /analyze:
C6340: Mismatch on sign: 'const unsigned int' passed as _Param_(4) when
some signed type is required in call to 'fprintf'.
Change-Id: I5f1fad4c93745baf17d70178a5e66579ccd2b155
This is because, FlattenSimilarBlocks() replaces some opaque pixels by
transparent ones. This results in an equivalent output only if blending
is turned on for the current frame.
Change-Id: I05612c952fdbd4b3a6e0ac9f3a7d49822f0cfb9b
Snapping odd offsets in GIF to even offsets in WebP was causing extra row/column
being disposed in such cases.
Code is rewritten to maintain previous and current canvas (it used to maintain
previous canvas and current frame earlier). And we recompute change rectangles
as those from GIF may no longer apply.
Also, this renders methods like ReduceTransparency() and ConvertToKeyFrame()
redundant, as internally maintained current canvas is always independent of
previous canvases.
Disposal method choice: we pick the disposal method that results in the smallest
change rectangle.
Change-Id: Ic31186d98fe1a2a790a89d1571b17e3abd127e79
For some GIF images, the first frame is missing the corresponding
graphic control extension. For such cases, we were never calling
GetBackgroundColor(), and default background color value (white) was being used
incorrectly.
So, we call GetBackgroundColor() when we encounter the first image
descriptor instead, to make sure that it is always called.
Change-Id: I00fc8e943d8a0c1578dcd718f3e74dec7de4ed61
put WebPMuxConfig on the stack in main() rather than allocating it in
InitializeConfig(); removes a level of indirection there.
Change-Id: I81d386f7472ebbd322dd3fdbfda9d78dbeb62a66
This compresses the uimage using lossless compression and controlable
decimating pre-process.
Code is under WEBP_EXPERIMENTAL_FEATURE while it's being experimented with.
Change-Id: I8b7f4cfcc3c6afc52a556102842bdbb045ed5ee8
* try to avoid trailing '.'
* rationalize capitalization
missed in:
0a8b886 dust up the help message
Change-Id: I6f80736cc8a2ff4f185f63d463a57d5bbf88a0db
+ vwebp's -help output
this is a future option; missed in:
793368e restore decode API compatibility
Change-Id: If920df2cf8de57ebad93a6b98830562149396d8d
We store the raw RGB samples decoded from JPEG, and avoid precision loss.
Note that this may increase the encoding time reported by
cwebp -v, since RGB->YUV now occur during WebPEncode call
(in case of lossy), instead of ReadJPEG().
This also increases the memory use, since we're carying the
source ARGB samples around.
Change-Id: Ic2180206cfc9f5574f391e91c3b89b9d81695d01
this defines WORDS_BIGENDIAN, replacing uses of
__BIG_ENDIAN__/__BYTE_ORDER__ with it
+ fixes lossless BGRA output with big-endian toolchains
that do not define __BIG_ENDIAN__ (codesourcery mips gcc)
Change-Id: Ieaccd623292d235343b5e34b7a720fc251c432d7
previously, the final canvas size was adjusted tightly from the
animation frames. Now, it can be specified separately (to be larger, in particular).
calling WebPMuxSetCanvasSize(mux, 0, 0) triggers the 'adjust tightly' behaviour.
This can be useful after calling WebPMuxCreate() if further image addition
is expected.
-> Fixed gif2webp accordingly.
also: made WebPMuxAssemble() more robust by systematically zero-ing WebPData.
Change-Id: Ib4f7eac372cf9dbf6e25cd686a77960e386a0b7f
