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Conversion Quality From JP2 to JPG
Posted: 2014-07-10T20:41:39-07:00
by hapiben
Hi,
We found an issue when we're downloading an image from one of our services. What we're trying to do is convert a .jp2 file to .jpg.
Using command conversion:
Imagemagick version 6.7.7-6
Upgrading Imagemagick to 6.8.9-1 will fix the issue, but I would like to know what causes the issue that I have. Does anyone here experienced the same issue?
Thanks,
Ben
Re: Conversion Quality From JP2 to JPG
Posted: 2014-07-10T20:48:23-07:00
by hapiben
More info about the image that I have. Running identify.
Code: Select all
Image: hires.jp2
Format: JP2 (JPEG-2000 File Format Syntax)
Class: DirectClass
Geometry: 3200x4912+0+0
Resolution: 72x72
Print size: 44.4444x68.2222
Units: Undefined
Type: TrueColor
Endianess: Undefined
Colorspace: RGB
Depth: 16-bit
Channel depth:
red: 16-bit
green: 16-bit
blue: 16-bit
Channel statistics:
Red:
min: 0 (0)
max: 65535 (1)
mean: 35981.8 (0.549048)
standard deviation: 7127.47 (0.108758)
kurtosis: 0.945922
skewness: -0.322088
Green:
min: 0 (0)
max: 65535 (1)
mean: 33058.9 (0.504446)
standard deviation: 6901.91 (0.105316)
kurtosis: 1.22203
skewness: -0.137207
Blue:
min: 0 (0)
max: 65535 (1)
mean: 26976.1 (0.411629)
standard deviation: 6923.29 (0.105643)
kurtosis: 1.42752
skewness: 0.0320182
Image statistics:
Overall:
min: 0 (0)
max: 65535 (1)
mean: 32005.6 (0.488374)
standard deviation: 6984.96 (0.106584)
kurtosis: 2.73838
skewness: -0.177046
Rendering intent: Undefined
Gamma: 1
Interlace: None
Background color: rgb(255,255,255)
Border color: rgb(223,223,223)
Matte color: rgb(189,189,189)
Transparent color: rgb(0,0,0)
Compose: Over
Page geometry: 3200x4912+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG2000
Orientation: Undefined
Properties:
date:create: 2014-07-11T10:16:38+12:00
date:modify: 2014-07-11T10:03:43+12:00
signature: 65b80d39aaa1c5d401e5c81984dece73f6835efb10c3736872c0e09919645203
Profiles:
Profile-icc: 544 bytes
Description: Adobe RGB (1998)
Manufacturer: Adobe RGB (1998)
Model: Adobe RGB (1998)
Copyright: (c) 2000 Adobe Systems Inc.
Artifacts:
filename: hires.jp2
verbose: true
Tainted: False
Filesize: 19.42MB
Number pixels: 15.72M
Pixels per second: 2.159MB
User time: 7.250u
Elapsed time: 0:08.279
Version: ImageMagick 6.7.7-6 2014-07-11 Q16 http://www.imagemagick.org
Re: Conversion Quality From JP2 to JPG
Posted: 2014-07-10T21:25:40-07:00
by fmw42
At that old release, IM was using the Jasper delegate library, which did not support the advanced features that are in JPEG 2000. The OpenJpeg used now in current releases supports most of the advance features.
See the table near the bottom of
http://en.wikipedia.org/wiki/JPEG2000
Re: Conversion Quality From JP2 to JPG
Posted: 2014-07-13T14:10:17-07:00
by hapiben
Hi fmw42, thanks for the info.
I appreciate it. I also found at the bottom of the Wiki that jp2 on Jasper have some issues with 16-bit image conversion.