YCbCr in JPEG compressed TIFF fail to be detected

[cedricm]

Hi,

I've a set of TIFF files containing JPEG encoded images in the YCbCr color space that don't get properly read/resized by ImageMagick. I get some color cast in the output due to wrong color space.
Other tools like The Gimp are fine with those images.

Using either ImageMagick 6.7.7-10 or 6.8.0-2, I can get ImageMagick process those images properly only if I force the YCbCr colorspace:
$ convert source.tif -set colorspace YCbCr -resize 800x600 out.jpg

With ImageMagick 6.6.9-7, I couldn't get correct colors at all (any idea of how I can process them with this version?).

Running ImageMagick 6.8.0-2's identify gives the following:

$ identify -verbose source.tif
Image: source.tif
Format: TIFF (Tagged Image File Format)
Class: DirectClass
Geometry: 7210x5410+0+0
Resolution: 300x300
Print size: 24.0333x18.0333
Units: PixelsPerInch
Type: TrueColor
Base type: TrueColor
Endianess: MSB
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
[...]
Image statistics:
[...]
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)
Interlace: None
Background color: white
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Compose: Over
Page geometry: 7210x5410+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG
Orientation: TopLeft
Properties:
[...]
dc:format: image/tiff
exif:ApertureValue: 8
exif:ColorSpace: -1
exif:ExifVersion: 0210
[...]
jpeg:sampling-factor: 1x1
photoshop:ColorMode: 3
photoshop:DateCreated: 2009-07-19
photoshop:History:
photoshop:ICCProfile: Adobe RGB (1998)
[...]
tiff:artist: powerbook
tiff:Compression: 7
tiff:endian: msb
tiff:ImageLength: 5410
tiff:ImageWidth: 7210
[...]
tiff:photometric: YCBCR
tiff:PhotometricInterpretation: 6
tiff:PlanarConfiguration: 1
tiff:rows-per-strip: 48
tiff:SamplesPerPixel: 3
tiff:software: Adobe Photoshop CS3 Macintosh
[...]
Profiles:
Profile-8bim: 15644 bytes
Profile-icc: 560 bytes
Adobe RGB (1998)
Profile-iptc: 64 bytes
[...]
Profile-xmp: 16746 bytes
[...]
Version: ImageMagick 6.8.0-2 2012-10-26 Q16 http://www.imagemagick.org
$

ExifTool reports:
$ exiftool -a -G0 source.tif
[ExifTool] ExifTool Version Number : 8.60
[...]
[EXIF] Subfile Type : Full-resolution Image
[EXIF] Image Width : 7210
[EXIF] Image Height : 5410
[EXIF] Bits Per Sample : 8 8 8
[EXIF] Compression : JPEG
[EXIF] Photometric Interpretation : YCbCr
[...]
[EXIF] JPEG Tables : (Binary data 558 bytes, use -b option to extract)
[EXIF] Y Cb Cr Sub Sampling : YCbCr4:4:4 (1 1)
[EXIF] Y Cb Cr Positioning : Co-sited
[...]
[XMP] Format : image/tiff
[XMP] Date Created : 2009:07:19
[XMP] Color Mode : RGB
[XMP] ICC Profile Name : Adobe RGB (1998)
[XMP] History :
[XMP] Image Width : 7210
[XMP] Image Height : 5410
[XMP] Bits Per Sample : 8, 8, 8
[XMP] Compression : JPEG
[XMP] Photometric Interpretation : YCbCr
[XMP] Samples Per Pixel : 3
[XMP] X Resolution : 300
[XMP] Y Resolution : 300
[XMP] Resolution Unit : inches
[...]
$

From what I see, the colorspace reported by EXIF/XMP metadata is not used, and ImageMagick seems to think that the image is a sRGB one.

Thanks,

Cedric

[magick]

Post a URL to one or two of your images. We need to download them and reproduce the problem before we can comment.

[cedricm]

Hi,

Link to such an image sent in a private message!

Thanks!

[magick]

We can reproduce the problem you posted and have a patch in ImageMagick 6.8.0-4 Beta available within a few days. Thanks.

[cedricm]

That's great, thanks!!