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9 Commits

Author SHA1 Message Date
David Symonds
0351284b2d image: add import comments. 
Change-Id: I2d3a1d002ad43af24cd8b451a2cae4c217482675
Reviewed-on: https://go-review.googlesource.com/1237
Reviewed-by: Andrew Gerrand <adg@golang.org>
 2014-12-09 22:43:18 +00:00
Nigel Tao
8a2d4aba20 go.image/vp8: clamp the UV DC quantization factor to 132. 
This fixes the lossy_extreme_probabilities.webp conformance test.

LGTM=pascal.massimino, r
R=r, pascal.massimino
CC=golang-codereviews
https://golang.org/cl/145600043
 2014-10-01 09:39:28 +10:00
Nigel Tao
07fcf9c2fe vp8: skip filtering for all-zero-DC macroblock residuals. 
This makes the Go code match the libwebp C code's output on
blue-purple-pink-large.*-filter.lossy.webp

Also make the various WEBP benchmarks all decode a similar image,
the image at http://blog.golang.org/gophercon/image01.jpg, to make
it more meaningful to e.g. compare the simple filter's numbers with
the normal filter's numbers.

Also fix a "go vet" warning in webp/decode.go.

The test data was generated by:
wget http://blog.golang.org/gophercon/image01.jpg -O blue-purple-pink-large.jpeg
convert blue-purple-pink-large.jpeg blue-purple-pink-large.png
cwebp -lossless blue-purple-pink-large.png -o blue-purple-pink-large.lossless.webp
cwebp -q 80 -f 0 blue-purple-pink-large.png -o blue-purple-pink-large.no-filter.lossy.webp
cwebp -q 80 -strong blue-purple-pink-large.png -o blue-purple-pink-large.normal-filter.lossy.webp
cwebp -q 80 -nostrong blue-purple-pink-large.png -o blue-purple-pink-large.simple-filter.lossy.webp
dwebp -pgm blue-purple-pink-large.no-filter.lossy.webp -o tmp.pgm && convert tmp.pgm blue-purple-pink-large.no-filter.lossy.webp.ycbcr.png && rm tmp.pgm
dwebp -pgm blue-purple-pink-large.normal-filter.lossy.webp -o tmp.pgm && convert tmp.pgm blue-purple-pink-large.normal-filter.lossy.webp.ycbcr.png && rm tmp.pgm
dwebp -pgm blue-purple-pink-large.simple-filter.lossy.webp -o tmp.pgm && convert tmp.pgm blue-purple-pink-large.simple-filter.lossy.webp.ycbcr.png && rm tmp.pgm

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/106230044
 2014-06-30 10:36:25 +10:00
Rui Ueyama
dc115882f1 go.image/vp8: use branch-free abs 
This change seems to restore performance to
the level before CL 108140045.

benchmark                         old ns/op    new ns/op    delta
BenchmarkDecodeVP8SimpleFilter       796416       784394   -1.51%
BenchmarkDecodeVP8NormalFilter      4931138      4693078   -4.83%
BenchmarkDecodeVP8L                 7820030      7821796   +0.02%

LGTM=nigeltao, r
R=nigeltao, r
CC=golang-codereviews
https://golang.org/cl/107340047
 2014-06-30 10:33:37 +10:00
Nigel Tao
f8a86727c2 go.image/vp8: remove the filter look-up tables. 
The benchmarks are a little slower, but the code is shorter.

benchmark                          old ns/op     new ns/op     delta
BenchmarkDecodeVP8SimpleFilter     621950        644184        +3.57%
BenchmarkDecodeVP8NormalFilter     4045745       4269431       +5.53%

LGTM=r
R=r, minux, ruiu
CC=golang-codereviews
https://golang.org/cl/108140045
 2014-06-27 09:14:15 +10:00
Nigel Tao
0424e74a0e go.image/vp8: implement the normal filter. 
The testdata was generated via:
cwebp foo.png -o foo.lossy.webp
dwebp -pgm foo.lossy.webp -o tmp.pgm
convert tmp.pgm foo.lossy.webp.ycbcr.png
rm tmp.pgm

TBR=r
R=r
CC=golang-codereviews
https://golang.org/cl/107330043
 2014-06-26 13:29:30 +10:00
Nigel Tao
94ba43c478 go.image/vp8l: new package. 
The blue-purple-pink image comes from
http://blog.golang.org/gophercon

The tux and yellow_rose images come from
https://developers.google.com/speed/webp/gallery2 and according to
that page, those images are in the public domain.

The gopher-doc images are http://golang.org/doc/gopher/doc.png
after quantizing its palette to 2/4/16/256 colors.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/109010043
 2014-06-17 21:51:57 +10:00
Nigel Tao
72be9c51b1 go.image/vp8: implement the loop filter. 
The testdata files were created by:
cwebp video-001.png -o video-001.webp
dwebp -pgm video-001.webp -o tmp.pgm
convert tmp.pgm video-001.webp.ycbcr.png
rm tmp.pgm

LGTM=r
R=r
CC=chaishushan, golang-codereviews
https://golang.org/cl/91700044
 2014-05-27 10:52:02 +10:00
Nigel Tao
f93749e6f2 go.image/vp8, go.image/webp: new packages, copied from 
code.google.com/p/vp8-go

This is a straight copy, followed by import path updates.

LGTM=r
R=r, mirtchovski, oleku.konko
CC=golang-codereviews
https://golang.org/cl/79320043
 2014-03-25 13:29:48 +11:00