Evaluated the impact of this change over 1000 image corpus.
The compression density is up (on average) by 1.2% and encoding time has
gone down considerably from 716 ms (per file) to 146 ms (per file)
(4.9X improvement in encoding time).
Change-Id: Ida562cc0bfe18c9d6f5f00873c95f8396b480eab
Adds new methods WebPPictureARGBToYUVA() and WebPPictureYUVAToARGB()
Depending on the value of picture->use_argb_input,
the main call WebPEncode() will convert appropriately.
Note that both conversions are lossy, so it's recommended to:
* use YUVA input for lossy compression (picture->use_argb_input=0)
* use ARGB input for lossless compression (picture->use_argb_input=1)
Change-Id: I8269d607723ee8a1136b9f4999f7ff4e657bbb04
this is more a workaround than a fix. this change forces the tables
from yuv.h into the data section rather than generating them as common
blocks. prior to this the linkage would fail with e.g.,
Undefined symbols:
...
"_VP8kClip4Bits", referenced from:
_Yuv444ToRgba4444 in libwebp.a(libwebpdsp_la-upsampling.o)
broken since:
48f8275 add colorspace for premultiplied alpha
Change-Id: I69c36758c31cd3a4b3ea5c412674d1a47b45447e
- Add details about the VP8L chunk support.
- Also add new example bitsteams containing VP8L chunk.
- Add back a section describing the VP8 chunk.
- Restrict some fields to 16 or 24 bits instead of 32 bits.
- Fields whose values are always positive are stored 1-based
instead of 0-based.
- Unknown chunks can only occur at certain places in the file.
- Remove the restriction for some fields to be divisible by 32 or 16.
Instead they are restricted to be even.
- Add a restriction for (canvas_width * canvas_height) product.
- Add 3 bits for rotation & symmetry in VP8X flags.
- Add some new example layouts.
- Add/clarify some nitty-gritties throughout the doc.
- Use the terms frame/tile more consistently and logically.
- Update related TODOs.
Change-Id: I611c1f58ecc3ee87546ca31bad1609376fad251e
* add a real proper pointer for holding memory chunk pointer
(instead of using y and argb fields)
* polish the doc with details
* add a WebPPictureView() that extract a view from a picture
without any copy (kind of a fast-crop).
* properly snap the top-left corner for Crop/View. Previously,
the luma position was not snapped, and was off compared to the chroma.
Change-Id: I8a3620c7f5fc6f7d1f8dd89d9da167c91e237439
Example kramdown command line to apply syntax highlighting requires
kramdown latest. Command is slightly different for earlier versions.
modified: doc/README
Change-Id: Icda1197436b5c5ed936ceff53c1dc51aa4ce409b
'Set' and 'Get' methods for images take/return a bitstream as input,
instead of separate 'image' and 'alpha' arguments.
Also,
- Make WebPDataCopy() a public API
- Use WebPData for storing data in WebPChunk.
- Fix a potential memleak.
Change-Id: I4bf5ee6b39971384cb124b5b43921c27e9aabf3e
Substantial edit, though less than 100% thorough. This
makes changes that are clearly safe, but avoids others
where my domain knowledge is incomplete and accuracy
might be compromised.
modified: doc/webp-lossless-bitstream-spec.txt
Change-Id: I89361a2e1157b8d2e44a8b4f4603f65833f0c1e6
Check for valid bounds on the 'dist' in backward reference case.
Clamp it to 1 in case of zero and negative values.
Change-Id: I78e956d4595955efa02b1f9628b475093f6ee001
