Closed
Description
Please answer these questions before submitting your issue. Thanks!
What version of Go are you using (go version)?
master
What operating system and processor architecture are you using (go env)?
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/tbonfort/dev/go"
GORACE=""
GOROOT="/usr/lib/go-1.6"
GOTOOLDIR="/usr/lib/go-1.6/pkg/tool/linux_amd64"
GO15VENDOREXPERIMENT="1"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"
What did you do?
func BenchmarkEncodeYCbCr(b *testing.B) {
b.StopTimer()
img := image.NewYCbCr(image.Rect(0, 0, 640, 480), image.YCbCrSubsampleRatio420)
bo := img.Bounds()
rnd := rand.New(rand.NewSource(123))
for y := bo.Min.Y; y < bo.Max.Y; y++ {
for x := bo.Min.X; x < bo.Max.X; x++ {
cy := img.YOffset(x, y)
ci := img.COffset(x, y)
img.Y[cy] = uint8(rnd.Intn(256))
img.Cb[ci] = uint8(rnd.Intn(256))
img.Cr[ci] = uint8(rnd.Intn(256))
}
}
b.SetBytes(640 * 480 * 4)
b.StartTimer()
options := &Options{Quality: 90}
for i := 0; i < b.N; i++ {
Encode(ioutil.Discard, img, options)
}
}
What did you expect to see?
jpeg.Encode() of *image.YCbCr should be faster than for *image.RGBA
What did you see instead?
This is slow as jpeg.Encode() uses the generic image.At() which involves unnecessary ycbr->rgba->ycbcr conversions, and more importantly image.color allocations