[Ssc-dev] packing & unpacking region redaction information.

[Andrew Senior]

Hi Harlo,
I just pushed a new version of JpegRedactionLibrary to github which can
take all the redaction region information, including the info needed to
unredact those regions, and pack it up into a
binary blob. If given a binary blob of such data it can unpack it and
reverse the redaction.  This is still limited to blobs < 64KB, but shows
you how it could work.
Let me know if this is useful, or you need something different. I hope to
get rid of the size limit in the next day or two.

See the example code at:
https://github.com/asenior/Jpeg-Redaction-Library/blob/master/test/metadatatest.cpp#L77

it redacts an image "original" and the redaction data in redaction is
packed into a blob redaction_pack, which is then stored in the image and
saved.
      std::vector<unsigned char> redaction_pack;
      redaction.Pack(&redaction_pack);
      printf("Packed redaction object is %d bytes\n", redaction_pack.size
());
      original.SetObscuraMetaData(redaction_pack.size(),
 &redaction_pack.front());

later on that process is reversed and the image is restored. As I
understand it you want to get the redaction_pack & encrypt it then add your
own metadata before passing it back as "ObscuraMetaData".

there's also this sample code
https://github.com/asenior/Jpeg-Redaction-Library/blob/master/test/test_utils.cpp#L162
called from here:
https://github.com/asenior/Jpeg-Redaction-Library/blob/master/test/test_redaction.cpp#L39
that does the same operation without the intermediate save to disk.

Andrew
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