The output was always 99dB because the lossless pipeline is not
modifying the 'picture'. Changing that is not that simple because
near_lossless impacts both VP8ApplyNearLossless() and
ApplyPredictFilter(); the latter cannot be applied as is to the input
and thus the final modified 'picture' cannot be easily retrieved
without decoding the encoded bitstream. Hence ReadWebP() is called in
cwebp.c on the encoded bitstream kept in memory to get the correct
distortion.
However -get_psnr returns a different distortion than get_disto for
lossy encoding configurations because cwebp loads the source as YUV
while get_disto directly reads it as RGB without conversion loss.
Change-Id: I5c32cf8f89eb137973dc7eebda747682d921b8e2
This is particularly useful for multi-pass search (but not only),
to prevent the search from going over or below a reasonable threshold.
E.g.: 'cwebp -qrange 50 80 ...' will prevent any unreasonable degradation.
new cwebp option: -qrange min max
Change-Id: I59f394533535fc20b6996bc0895f4301476d5eff
Define macros in examples/unicode.h to use Unicode argv
on Windows. Keep char everywhere on Unix since it handles
UTF-8 without any change.
Impact:
- All fopen () and SHCreateStreamOnFile(),
- All fprintf() printing file paths,
- All strcmp() used with "-",
- File path parsing,
- Gif reading.
Concerned executables from examples/ and extras/:
anim_diff, anim_dump, vwebp, vwebp_sdl,
cwebp, dwebp, gif2webp, img2webp,
webpmux, webpinfo, webp_quality, get_disto
When compiled on Windows with Unicode enabled, webpmux and
img2webp will not work when used with an argument file and
will print "Reading arguments from a file is a feature
unavailable with Unicode binaries."
BUG=webp:398
Change-Id: Ic55d222a3ce1a715f9c4cce57ecbe2705d5ce317
Fix issue where color data is discarded in fully transparent
areas when -resize -exact.
BUG=webp:397
Change-Id: I58ce8d5ae172d5d0f0138e07c7df3a3c6cbd0019
For large images overflowing the partition0, we re-do a number
of passes but were forgetting to reset the block_count[].
This was leading to incorrect summary.
+ some cosmetic fixes here and there
BUG=webp:355
Change-Id: Ie87158d7f177f8efdca429b146cfcd0e81652d2f
the incorrect bit was being extracted from the lossless bitstream header
causing the alpha flag in VP8X to be misreported. previously the
signature byte was ignored in the calculation of the offset.
since:
8ba1bf61 Stricter check for presence of alpha when writing lossless
images
BUG=webp:361
Change-Id: I7c618b5f01a37f5e4b799dee11a7949efaf88046
Make WebPPictureDistortion() only compute distortion on A/R/G/B planes, not Y/U/V(A).
(not just for SSIM, but PSNR too).
This is to avoid problems with using SSIM on U/V channels.
If Y/U/V distortion is needed, one can always use WebPPlaneDistortion() individually.
Change-Id: If8bc9c3ac12a8d2220f03224694fc389b16b7da9
Also introduce an always-failing 'reader' for unknown formats.
So we don't have to check reader==NULL, code is more regular.
-> We can get read of specific ReadPNG(), ReadJPEG(), ... declaration and use.
Change-Id: I290759705420878f00c7223c726d4ad404afd9c4
decoding and file i/o have been split to imageio, all that remains is
some string routines used for parameter parsing in the examples
Change-Id: I77386cd8aa39124b9e14c95fdbaa17ea4ab5bb24
-> WebPImageReader
Introduce a variant of image-guessing function that returns a reader
directly: WebPGuessImageReader()
Change-Id: I5ddc53024fcf941e33d997b2be6aa1a963d939ab
adds a generic examples/image_dec.[ch] entry point too.
WebPGuessImageType() can be used to infer image type.
Change-Id: I8337e7b6ad91863c9cf118e4791668d2d175079b
This is to prevent users shooting in the foot using -psnr or
-size alone and not getting the expected result.
Change-Id: I67a3289e4ec0a2a813c98807f2ec5e600f52dc63
we map the input file into memory, even in the non-stdin case.
This is less efficient than letting the png/jpeg/... decoding libraries
use fread()'s, but more general.
Change-Id: I4501cb9a1daf69593eb8e3326c115cd8cbdf92fd
-> read is a bit slower (memory allocation and such) than reading directly from disk.
-> we're not yet ready to accept stdin as input (-- -) because we still need to guess
the file type with GetImageType(). And since we can't rewind on stdin, this will need
a bit more work before being able to read from stdin.
Change-Id: I6491fac4b07d28d1854518325ead88669656ddbf
Rename the flag to exact instead of the opposite cleanup_alpha. Add the flag to
WebPConfig. Do the cleanup in the webp encoder library rather than the cwebp
binary, this will be needed for the next stage: smarter alpha cleanup for
better compression which cannot be done as a preprocessing due to depending on
predictor choices in the encoder.
Change-Id: I2fbf57f918a35f2da6186ef0b5d85e5fd0020eef
This is to infer the needed conversion to YUV(A) or RGB(A).
This is useful to avoid some conversion steps between ARGB and YUVA.
For instance, if the input file is a JPEG, we decode to RGB and
convert to YUV right away, without the intermediate step to ARGB.
The only caveat is that cropping/scaling might give slightly different result,
because of YUV420 downsampling. Therefore, we omit this feature
at cwebp level, when -crop or -rescale is used.
Change-Id: I5a3abe5108982f2a4570e841e3d9baffc73f5bee
using a *tmp_plane buffer to split a/r/g/b planes up appeared to
be the easiest route, compared to copy-pasting the whole code and
making it x_stride aware...
Change-Id: I0898ef1df62bd3e1713b77187b31b5eeef3832fe
Updated the near-lossless level mapping and make it correlated to lossy
quality i.e 100 => minimum loss (in-fact no-loss) and the visual-quality loss
increases with decrease in near-lossless level (quality) till value 0.
The new mapping implies following (PSNR) loss-metric:
-near_lossless 100: No-loss (bit-stream same as -lossless).
-near_lossless 80: Very very high PSNR (around 54dB).
-near_lossless 60: Very high PSNR (around 48dB).
-near_lossless 40: High PSNR (around 42dB).
-near_lossless 20: Moderate PSNR (around 36dB).
-near_lossless 0: Low PSNR (around 30dB).
Change-Id: I930de4b18950faf2868c97d42e9e49ba0b642960
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
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
