我使用此代码调整300kb的动画gif大小，但生成的gif为40mb +。
$image = new \Imagick($sSourceFile);
// split
$image = $image->coalesceImages();
// resize each frame
foreach ($image as $key => $frame) {
$frame->thumbnailImage(904, 678);
$frame->setImagePage(904, 678, 0, 0);
}
// find areas that has changed between images
$image = $image->deconstructImages();
// save
$image->writeImages($sTargetFile, true);
我在阅读http://www.imagemagick.org/Usage/anim_opt/#frame_opt
之后尝试优化相框$image = $image->optimizeImageLayers(); //instead of deconstructImages()
但这并没有帮助。
还有其他方法可以优化帧吗？
我尝试在没有php插件的情况下修复它：
$command = "convert " . $sSourceFile . " -coalesce";
$command .= " -resize 904x678";
$command .= " -layers OptimizeFrame " . $sTargetFile;
system($command);
这适用于50kb的小型GIF，但是在我的更大的那个上失败了这条消息：
PHP Warning: system(): Unable to fork [convert /var/www/my_folder/orig.gif -coalesce -layers OptimizeFrame /var/www/my_folder/new.gif] in /var/www/my_folder/test.php on line 100
imagemagick identity命令在我的新旧GIF上给出了以下内容：
old.gif[0] GIF 904x678 904x678+0+0 8-bit sRGB 256c 321KB 0.010u 0:00.019
old.gif[1] GIF 2x3 904x678+516+430 8-bit sRGB 256c 321KB 0.040u 0:00.049
old.gif[2] GIF 4x5 904x678+515+429 8-bit sRGB 256c 321KB 0.040u 0:00.049
old.gif[3] GIF 6x7 904x678+514+428 8-bit sRGB 256c 321KB 0.040u 0:00.049
old.gif[4] GIF 8x9 904x678+513+427 8-bit sRGB 256c 321KB 0.040u 0:00.049
...
old.gif[480] GIF 236x45 904x678+288+552 8-bit sRGB 256c 321KB 0.030u 0:00.029
old.gif[481] GIF 232x45 904x678+288+552 8-bit sRGB 256c 321KB 0.030u 0:00.029
old.gif[482] GIF 1x1 904x678+0+0 8-bit sRGB 256c 321KB 0.030u 0:00.029
old.gif[483] GIF 1x1 904x678+0+0 8-bit sRGB 256c 321KB 0.030u 0:00.029
old.gif[484] GIF 1x1 904x678+0+0 8-bit sRGB 256c 321KB 0.030u 0:00.029
new.gif[0] GIF 904x678 904x678+0+0 8-bit sRGB 64c 48.27MB 0.030u 0:00.040
new.gif[1] GIF 904x678 904x678+0+0 8-bit sRGB 64c 48.27MB 0.060u 0:00.060
new.gif[2] GIF 904x678 904x678+0+0 8-bit sRGB 64c 48.27MB 0.060u 0:00.060
new.gif[3] GIF 904x678 904x678+0+0 8-bit sRGB 64c 48.27MB 0.060u 0:00.060
new.gif[4] GIF 904x678 904x678+0+0 8-bit sRGB 128c 48.27MB 0.060u 0:00.060
...
new.gif[480] GIF 904x678 904x678+0+0 8-bit sRGB 256c 48.27MB 0.030u 0:00.039
new.gif[481] GIF 904x678 904x678+0+0 8-bit sRGB 256c 48.27MB 0.030u 0:00.039
new.gif[482] GIF 904x678 904x678+0+0 8-bit sRGB 256c 48.27MB 0.030u 0:00.039
new.gif[483] GIF 904x678 904x678+0+0 8-bit sRGB 256c 48.27MB 0.030u 0:00.039
new.gif[484] GIF 904x678 904x678+0+0 8-bit sRGB 256c 48.27MB 0.030u 0:00.039
使用ImageMagick 6.8.7-7 Q16 x86_64 2013-11-27。
在识别中添加--verbose会给我：
Image: new.gif
Format: GIF (CompuServe graphics interchange format)
Mime type: image/gif
Class: PseudoClass
Geometry: 904x678+0+0
Units: Undefined
Type: Palette
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Red:
min: 199 (0.780392) max: 250 (0.980392) mean: 236.67 (0.928118) standard deviation: 10.9591 (0.0429769) kurtosis: 0.887823 skewness: -1.55982
Green:
min: 199 (0.780392) max: 250 (0.980392) mean: 236.67 (0.928118) standard deviation: 10.9591 (0.0429769) kurtosis: 0.887823 skewness: -1.55982
Blue:
min: 199 (0.780392) max: 249 (0.976471) mean: 236.647 (0.928027) standard deviation: 10.9867 (0.0430852) kurtosis: 0.857301 skewness: -1.5512 Image statistics:
Overall:
min: 199 (0.780392) max: 250 (0.980392) mean: 236.662 (0.928087) standard deviation: 10.9683 (0.0430131) kurtosis: 0.877615 skewness: -1.55695 Colors: 34
Histogram:
4: (199,199,199) #C7C7C7 grey78
272: (203,203,203) #CBCBCB srgb(203,203,203)
... [long list removed by Tieme]
199: (249,249,249) #F9F9F9 srgb(249,249,249)
29: (250,250,246) #FAFAF6 srgb(250,250,246)
Colormap entries: 64
Colormap:
0: (199,199,199) #C7C7C7 grey78
1: (201,201,201) #C9C9C9 grey79
... [long list removed by Tieme]
62: ( 0, 0, 0) #000000 black
63: ( 0, 0, 0) #000000 black
Rendering intent: Perceptual
Gamma: 0.454545
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Background color: grey78
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 904x678+0+0
Dispose: None
Delay: 5x100
Iterations: 0
Scene: 0 of 485
Compression: LZW
Orientation: Undefined
Properties:
date:create: 2014-04-09T21:12:21+02:00
date:modify: 2014-04-09T21:12:21+02:00
signature: 6d2f4f19412c6187c28ee6ef8e71e7c59e166ab7bf151bb1ae2ab3701aff425c
Artifacts:
filename: new.gif
verbose: true
Tainted: False
Filesize: 48.27MB
Number pixels: 613K
Pixels per second: 113KB
User time: 5.370u
Elapsed time: 0:06.430
Version: ImageMagick 6.8.7-7 Q16 x86_64 2013-11-27 http://www.imagemagick.org
对于old.gif：
Image: old.gif
Format: GIF (CompuServe graphics interchange format)
Mime type: image/gif
Class: PseudoClass
Geometry: 904x678+0+0
Units: Undefined
Type: PaletteAlpha
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
alpha: 1-bit
Channel statistics:
Red:
min: 199 (0.780392) max: 251 (0.984314) mean: 236.67 (0.928118) standard deviation: 10.8629 (0.0425998) kurtosis: 0.97992 skewness: -1.63289
Green:
min: 199 (0.780392) max: 251 (0.984314) mean: 236.67 (0.928118) standard deviation: 10.8629 (0.0425998) kurtosis: 0.97992 skewness: -1.63289
Blue:
min: 199 (0.780392) max: 251 (0.984314) mean: 236.647 (0.928027) standard deviation: 10.9006 (0.0427473) kurtosis: 0.938884 skewness: -1.62081
Alpha:
min: 255 (1) max: 255 (1) mean: 255 (1) standard deviation: 0 (0) kurtosis: 0 skewness: 0 Image statistics:
Overall:
min: 0 (0) max: 251 (0.984314) mean: 177.497 (0.696066) standard deviation: 9.41846 (0.0369351) kurtosis: 32894 skewness: -1470.41 Colors: 50
Histogram:
4: (199,199,199,255) #C7C7C7 grey78
5: (201,201,201,255) #C9C9C9 grey79
... [long list removed by Tieme]
1: (250,250,246,255) #FAFAF6 srgba(250,250,246,1)
1: (251,251,251,255) #FBFBFB srgba(251,251,251,1)
Colormap entries: 256
Colormap:
0: (225,225,223,255) #E1E1DF srgba(225,225,223,1)
1: (214, 72, 68,255) #D64844 srgba(214,72,68,1)
... [long list removed by Tieme]
254: (242,242,242,255) #F2F2F2 grey95
255: (255,255,255, 0) #FFFFFF00 srgba(255,255,255,0)
Rendering intent: Perceptual
Gamma: 0.454545
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Background color: srgba(255,255,255,0)
Border color: srgba(223,223,223,1)
Matte color: grey74
Transparent color: srgba(255,255,255,0)
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 904x678+0+0
Dispose: None
Delay: 5x100
Iterations: 0
Scene: 0 of 485
Compression: LZW
Orientation: Undefined
Properties:
date:create: 2014-04-10T09:35:49+02:00
date:modify: 2014-04-03T11:42:15+02:00
signature: 5edcc0c3235de10a527f91b246054e2b15d17d16287ddc74001be7f7e9381c0a
Artifacts:
filename: old.gif
verbose: true
Tainted: False
Filesize: 321KB
Number pixels: 613K
Pixels per second: 5.108MB
User time: 0.080u
Elapsed time: 0:01.120
Version: ImageMagick 6.8.7-7 Q16 x86_64 2013-11-27 http://www.imagemagick.org