At the time of decoding webp file, if chunkID is not one of
{'ALPH', 'VP8', 'VP8L', 'VP8X'} return errInvalidFormat
Fixesgolang/go#10384
Change-Id: I167909b5ddef174d161f806297a08fac6aabcf19
Reviewed-on: https://go-review.googlesource.com/9839
Reviewed-by: Nigel Tao <nigeltao@golang.org>
This fixes all three lossy_alpha*.webp conformance tests.
The test data was generated by cwebp/dwebp version 0.4.1:
cwebp yellow_rose.png -o yellow_rose.lossy-with-alpha.webp
dwebp yellow_rose.lossy-with-alpha.webp -pgm -o tmp.pgm
convert tmp.pgm yellow_rose.lossy-with-alpha.webp.nycbcra.png
LGTM=pascal.massimino, r
R=r, pascal.massimino
CC=golang-codereviews
https://golang.org/cl/154350043
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
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