not exactly same.
Based on lossy WebP quality setting, ignore minor differences when
flattening
similar blocks.
For 6k set, at default quality with '-min_size' option, improves
compression by 0.3%
Change-Id: Ifcb64219f941e869eb2643e231220b278aad4cd4
there's some subtle changes:
- DecodeAlphaData() may be called with pos==end because we don't want
to decode more data (there's none left), but because we want to apply
process_func() to all the unprocessed pixels already decoded
- last_row is exclusive and should be understood as 'up to last_row'. Can be misleading.
- VP8LDecodeAlphaImageStream() was testing dec->last_pixel_ for completion,
which was wrong because last_pixel_ is the last *decoded* pixel, not the
last *processed* one. -> test now uses last_row_, as expected
Change-Id: I1fb04ba25cd7a4775db9e3deee3e2ae80f9c0a75
this might change some crc slightly, since WebPDequantizeLevels()
performs an analysis pass, counting levels, which impacts the smoothing.
Now, the cropping area is not the same, so minor diffs are expected here
and there.
Change-Id: I3cce1e40c6f11c25b7c841044d637685c5740352
* make ALPHNew/Delete static
* properly init ALPHDec::io_
* introduce AllocateAlphaPlane() and WebPDeallocateAlphaMemory()
* reorganize VP8DecompressAlphaRows()
but we're still allocate the full alpha-plane. Optim will come
in another patch since it's tricky
Change-Id: Ib6f190a40abb7926a71535b0ed67c39d0974e06a
this change will be superseded by patch #335160 eventually, but until then
let's fix the problem temporarily.
Change-Id: Iafd979c2ff6801e3f1de4614870ca854a4747b04
When FlattenSimilarBlocks() was making some blocks transparent with
averaged RGB values, filtering in lossy compression was causing
blockiness just outside the edge of these blocks.
Disabling filtering for that particular case avoid these block
artifacts.
The total encoded size of the 6k GIF set remains roughly the same (in
fact, reduces a bit).
Change-Id: Ida71cbabd59d851e16d871f53d19473312b3cc77
We pick a mapping with quality 0 mapping to max diff 32, to quality 100
mapping to max_diff 1.
For 6k GIF image set, this improves compression by:
4% at quality 0
0.05% at quality 75
Benefits the MovingThumbnailer test videos too.
Change-Id: I6838ce864d41e1e65311d26b9b8115a12390a253
This way we can ignore some noisy pixels and get tighter frame
rectangles.
Some results:
- Correctness:
Tested that anim_diff reports all images are identical for lossless, and
similar min_psnr value for lossy and mixed modes.
Also checked output images visually to make sure there weren't any
obvious kinks.
- Compression:
A very tiny improvement for 6000 image GIF set we have (0.03%) for lossy
and mixed mode. For some of these images, frames get dropped
automatically as they have a very small diff from previous frame.
10 images from test_video_frames_png show a clear improvement in
compression though. This CL leads to 7 out of 9 lossy WebPs getting
smaller -- for one of them, this leads to a higher quality being picked
(as that’s still < 150 KB).
Change-Id: If539b9e77e1375aa15edc8f926933593a9865f1c
and also pass 'VP8Io* io' extra param to VP8DecompressAlphaRows()
This is somehow in preparation for some memory optimizations in
the 'cropping' case. For now, only the easy crop_bottom case is
optimized.
Change-Id: Ib54531ba057bf62b98422dbb6c181dda626c72c2
This avoids generating file that would trigger a decoding bug
found in 0.4.0 -> 0.4.3 libwebp versions.
This reverts commit 6ecd72f845.
Change-Id: I4667cc8f7b851ba44479e3fe2b9d844b2c56fcf4
The mode's bits were not taken into account, which is ok for most of cases.
But in case of super large image, with 'easy' content, their overhead starts
mattering a lot and we were omitting to optimize for these.
Now, these mode bits have their own lambda values associated, limiting
the jerkiness. We also limit (for -m 2 only) the individual number of bits
to something that will prevent the partition 0 overflow.
removed the I4_PENALTY constant, which was a rather crude approximation.
Replaced by some q-dependent expression.
fixes issue #289
Change-Id: I956ae2d2308c339adc4706d52722f0bb61ccf18c
If value is '2', it means the buffer is a 'slow' one, like GPU-mapped memory.
This change is backward compatible (setting is_external_memory to 2
will be a no-op in previous libraries)
dwebp: add flags to force a particular colorspace format
new flags is:
-pixel_format {RGB,RGBA,BGR,BGRA,ARGB,RGBA_4444,RGB_565,
rgbA,bgrA,Argb,rgbA_4444,YUV,YUVA}
and also,external_memory {0,1,2}
These flags are mostly for debuggging purpose, and hence are not documented.
Change-Id: Iac88ce1e10b35163dd7af57f9660f062f5d8ed5e
This is in preparation for some SSE2 code.
And generally speaking, the whole SSIM code needs some
revamp: we're not averaging the SSIM value at each pixels
but just computing the overall SSIM value once, for the whole
plane. The former might be better than the latter.
Change-Id: I935784a917f84a18ef08dc5ec9a7b528abea46a5
based on the sse2 change in:
9960c31 Remove an unnecessary transposition in TTransform.
~9-10.5% faster at the function-level, < 1% overall
Change-Id: I44413369b230b250fb0dbc51ff2f17cfeda609b7
- The result is now indeed closest among possible results for all inputs, which
was not the case for bits>4, where the mapping was not even monotonic because
GetValAndDistance was correct only if the significant part of initial fit in
a byte at most twice.
- The set of results for a larger number of bits dropped is a subset of values
for a smaller number of bits dropped. This implies that subsequent
discretizations for a smaller number of bits dropped do not change already
discretized pixels, which improves the quality (changes do not accumulate)
and compression density (values tend to repeat more often).
- Errors are more fairly distributed between upwards and downwards thanks to
bankers’ rounding, which avoids images getting darker or lighter in overall.
- Deltas between discretized values are more repetitive. This improves
compression density if delta encoding is used.
Also, the implementation is much shorter now.
Change-Id: I0a98e7d5255e91a7b9c193a156cf5405d9701f16
Pass them along to internal 'pic' object, so that progress can be reported back
and user data can also be inspected.
Change-Id: Idb5d0d4a76d07283d704a86c5892e1ad7bda09fa
SSE4.1 is slower than the SSE2 implementation and this seems to
be due to a slow _mm_loadl_epi64 implementation by gcc
(hence a bug with my gcc 4.8) and a very slow _mm_hadd_epi32. Both
got confirmed by IACA and experiments.
Change-Id: I05607f66b7ccd8f4f42e000693aea583ffd5768f
