These are presets for lossless coding, similar to zlib.
The shortcut for lossless coding is now, e.g.:
cwebp -z 5 in.png -o out_lossless.webp
There are 10 possible values for -z parameter:
0 (fastest, lowest compression)
to 9 (slowest, best compression)
A reasonable tradeoff is -z 6, e.g.
-z 9 can be quite slow, so use with care.
This -z option is just a shortcut for some pre-defined
'-lossless -m xx -q yy' combinations.
Change-Id: I6ae716456456aea065469c916c2d5ca4d6c6cf04
the -alpha_cleanup flag was ineffective since we switched cwebp
to using ARGB input always.
Original idea by David Eckel (dvdckl at gmail dot com)
Change-Id: I0917a8b91ce15a43199728ff4ee2a163be443bab
New API options: WebPDecoderOptions.flip and 'dwebp -flip ...'
it uses negative stride trick.
Also changed the decoder code to support user-supplied
buffers with negative stride, independently of the
WebPDecoderOptions.flip value.
Change-Id: I4dc0d06f0c87e51a3f3428be4fee2d6b5ad76053
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
-> helps debanding (sky, gradients, etc.)
This dithering can only be triggered when using -preset photo
or -pre 2 (as a preprocessing). Everything is unchanged otherwise.
Note that this change is likely to make the perceived PSNR/SSIM drop
since we're altering the input internally.
Change-Id: Id8d4326245d9b828141de162c94ba381b1fa5813
WebPDemuxPartial() returns NULL for both of the following cases:
- There was a parsing error.
- It doesn't have enough data to start parsing.
Now, one can differentiate between these two cases by checking the value
of 'state' returned by WebPDemuxPartial().
Change-Id: Ia2377f0c516b3fcfae475c0662c4932d2eddcd0b
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
The output surface CAN be changed inbetween calls to
WebPIUpdate() or WebPIAppend(), but with precautions.
Change-Id: I899afbd95738a6a8e0e7000f8daef3e74c99ddd8
new option: -blend_alpha 0xrrggbb
also: don't force picture.use_argb value for lossless. Instead,
delay the YUVA<->ARGB conversion till WebPEncode() is called.
This make the blending more accurate when source is ARGB
and lossy compression is used (YUVA).
This has an effect on cropping/rescaling. E.g. for PNG, these
are now done in ARGB colorspace instead of YUV when lossy compression
is used.
Change-Id: I18571f1b1179881737a8dbd23ad0aa8cddae3c6b
using token-buffer (that is: slightly more memory. O(output_size))
This change is ON by default. To return to previous behaviour, use
'cwebp -low_memory' or set config.low_memory to true.
Side-effect of this new mode: it forces 1 partition only (which was
default anyway), and makes some statistics about the bitstream
no longer available. cwebp will no longer report 'intra4-coeffs', etc.
This mode also doesn't work (yet) with multi-pass, and -low_memory
is currently forced for multi-pass.
also: reversed the flag: USE_TOKEN_BUFFER -> DISABLE_TOKEN_BUFFER
also: fixed the kAverageBytesPerMB estimate
Change-Id: I4ea80382038d6df4309663e0cb7bd88d9bca9cf1
Also tweak the code for single image and fragmented image cases, so that
dmux->num_frames_ is always correct.
Change-Id: I31e6904222e4d96a54a0d8c8aa73d43b7a9094e7
new option: 'cwebp -mt ...'
new config flag: config.thread_level
(allowed thread_level are 0 or 1 for now. Maybe more later...)
If -mt is activated (and WEBP_USE_THREAD is used for compile), the alpha-compression
will be done in parallel to RGB coding for lossy. Can save quite a bit of latency...
Has no effect for lossless encoding.
Change-Id: I769d0bf90e7380cf99344ad62cd77277f4df5a46
This option remaps internal parameters to better match
the expected compression curve of JPEG and produce output files
of similar size, but with better quality.
Change-Id: I96a1cbb480b1f6a0c6845a23c33dfd63f197b689
If a NULL pre-allocated buffer is passed, a buffer will be automatically
allocated.
+ add some parameter checks.
reported in http://code.google.com/p/webp/issues/detail?id=139
Change-Id: I9e14ed97db30ee12e46b5e92aac7eeaaeb99bfd5
- 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
This is a correction to the following change:
a00a3daf5b Use 'frgm' instead of 'tile' in
webpmux parameters
Change-Id: I8fa0bce98efdde38827fd25712017a98a6ea7388
- Allow a duration of 0
- Rename LOOP chunk to ANIM and add the background color field to it.
- Add a disposal method field for each animation frame.
- Modify webpmux.c binary interface to allow the input of background color
and disposal methods. Also make '-loop' and '-bgcolor' arguments optional
with some default values.
Change-Id: I807372a61cdb8a0d3080ae3552caf2848070bf4d
- Also, use the term 'fragments' instead of 'tiling' in code
- This makes code consistent with the spec.
Change-Id: Ibeccffc35db23bbedb88cc5e18e29e51621931f8
Use separate fourCCs "XMP " and "EXIF" instead of a common "META"
Also, some refactorization in webpmux.c
Change-Id: Iad3337e5c1b81e785c60670ce28b1f536dd7ee31
LSIM stands for "local similarity": before matching
a compressed pixel to the source, we search around in the source
and minimise the squared error. So, this is close to PSNR calculation,
but mitigates some of its limitations (pure translation and noise for instance).
There's a new -print_lsim option to cwebp too.
Change-Id: Ia38561034c7a90e71d2ea0f55bb1de527eda245b
Change-Id: I36d3765e94d2b5529b321c186ccee1744785c5b3
fixes:
error: ISO C++ forbids forward references to 'enum' types
since:
28d25c8 replace 'typedef struct {} X;" by "typedef struct X X; struct X {};"
For low-color images, it may be better to not use color-palettes.
Users should treat this as one another hint (as with Photo &
Picture) and another parameter for tuning the compression density.
The optimum compression can still be obtained by running (outer loop)
compression with all possible tunable parameters.
Change-Id: Icb1a4face2a84774e16e801aee4a8ae97e232e8a
also relocate user_data from WebPAuxStats to the WebPPicture struct to
make clearing easier while placing it closer to the progress hook with
which it's used.
prior to this change some spurious lossless data could be reported in
the lossy (sans alpha) encoding case. additionally user_data could be
lost during lossless encoding.
Change-Id: I929fae3dfde4d445ff81bbaad51445ea586dd80b
* Extend AuxStats with new fields
it's slightly ABI-incompatible, but i guess it's ok for 0.1.99+
I expect to add more stats later, possibly (predictor stats, etc.)
* Have cwebp report the features used by lossless
compression (either for alpha or full lossless coding)
* Print the PSNR for alpha (useful in case of -alpha_q)
* clean-up alpha.c signatures
+ misc cleanup (added const '* const ptr', etc.)
Change-Id: I157a21581f1793cb0c6cc0882e7b0a2dde68a970
* commit 'v0.1.99': (39 commits)
Update ChangeLog
add extra precision about default values and behaviour
header/doc clean up
Makefile.vc: fix webpmux.exe *-dynamic builds
remove INAM, ICOP, ... chunks from the test webp file.
harmonize authors as "Name (mail@address)"
makefile.unix: provide examples/webpmux target
update NEWS
README: cosmetics
man/cwebp.1: wording, change the date
add a very crude progress report for lossless
rename 'use_argb_input' to 'use_argb'
add some padding bytes areas for later use
fixing the findings by Frederic Kayser to the bitstream spec
add missing ABI compatibility checks
Doc: container spec text tweaks
add ABI compatibility check
mux.h: remove '* const' from function parameters
encode.h: remove '* const' from function parameters
decode.h: remove '* const' from function parameters
...
Conflicts:
src/mux/muxinternal.c
Change-Id: I635d095c451742e878088464fe6232637a331511
Put emphasis on RGBA decoding instead of RGB/BGR
Clarify doc at some rough spots
Misc typo fix and cosmetics
Change-Id: Ic5fcfcc5bf4d612c5de23b0a5499f1fadde55bfe
- WEBP_MUX_INVALID_PARAMETER: was used only at one place, and that too
should actually be an assert().
- WEBP_MUX_ERROR: was never used.
Change-Id: I8883cb4dfae7a7918507501f21fced0c04dda36a
minor revision shouldn't matter, we only check major revision number.
Bumped all version numbers so that incompatibility starts *now*
Change-Id: Id06c20f03039845ae4cfb3fd121807b931d67ee4
the VP8 decode functions do not need to be public; only
GetInfo/CheckSignature need to be marked extern as they're used by
libwebpmux.
Change-Id: Id9ab4d6166b0271cf5d04563c6dac1fcc84adbdc
- Match offsets, duration, width/height for frames/tiles and enforce
some constraints.
- Note that this also means using 'int's instead of 'uint32_t's for
16-bit and 24-bit fields.
Change-Id: If0b229ad9fce296372d961104aa36731a3b1304b
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
* 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
'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
