As I have shown already, a simple statement converts the AP JPEG into a 200 ppi version, with YCbCr4:2:2 and the exact Quantization matrix.
Of course, our friend insisted that ABC news would not be using such a freetoy, ignorant perhaps of the fact that the code is based on the IJG software (Independent JPEG Group) and the same Quantization Matrix also shows up in Irfanview (Windows), GIMP (Windows/Mac) and some other packages.
What was also interesting that I fed the Xerox JPEG to the same software and it failed to find any matches for the quantization signature… This further strengthens the findings of the embedded comment and the quantization matrix as being unique to Xerox or at least a reliable detector.
And so we continue to chip away at the few issues that our friend tries to raise to support his ‘hypotheses’, and which continue to fail ever so slightly…
For helping strengthen the workflow, we should recognize Hermitian as a wonderful contributor.
The tool I am talking about is jpegsnoop and I have run it against:
AP110427018673.jpg – Save as 09
ap_obama_certificate_dm_110427-000.jpg – Quality 77
- IJG Library
4db82608b486f-000.jpg- No identification
birth-certificate-long-form-000.jpg – No identification