Alternatives for Extracting EXIF and JPEG Data from Images

[Roger]

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