Alternatives for Extracting EXIF and JPEG Data from Images

Max Erickson maxerickson at gmail.com
Mon Mar 5 01:16:11 CET 2007


Roger <crosseyedpenguin at cox.net> wrote:

> Does anybody have a pointer to a Python library/utility that will
> extract the chrominance and luminance quantization tables from
> JPG images? 
> 
> I have been using the _getexif method from PIL, which works fine,
> but doesn't extract the quantization data.  I am a bit fuzzy on
> the terminology, but the quantization data  seems to be JPEG data
> rather than EXIF data.  One utility that extracts the
> quantization tables is JPEGsnoop -- there is a link to download
> the utility here: 
>    http://www.impulseadventure.com/photo/jpeg-quantization.html
> 
> The source code for the above isn't available and may not be
> callable from a Python script even  if it were available.
> 
> Roger
> 

I don't know what the format is, etc, but jpegs I open with PIL have a 
quantization attribute, e.g:

>>> im.quantization
{0: array('b', [6, 4, 4, 5, 4, 4, 6, 5, 5, 5, 6, 6, 6, 7, 9, 14, 9, 9, 
8, 8, 9, 18, 13, 13, 10, 14, 21, 18, 22, 22, 21, 18, 20, 20, 23, 26, 
33, 28, 
<snip a bunch more numbers>


max




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