Andreas Meier created TIKA-2632:
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Summary: Analyze unknown govdocs files
Key: TIKA-2632
URL: https://issues.apache.org/jira/browse/TIKA-2632
Project: Tika
Issue Type: Improvement
Reporter: Andreas Meier
I recently started to analyze randomly govdocs1 files that could not be
recognized by TIKA properly.
This ticket should be used to identify problems with old or proprietary files
and to extend TIKA step-by-step if needed.
Stumbled across the following problems:
1. Old PowerPoint files (I expect Version 2.0 or 3.0) are not recognized
properly:
Found some mysterious files starting with 0xeddead0b and 0x0baddeed
Turned out that someone else already investigated this case a month ago:
[link
http://anjackson.net/2018/03/15/story-of-a-bad-deed/|http://anjackson.net/2018/03/15/story-of-a-bad-deed/]
The files are old PowerPoint. (PowerPoint 3.0 or 2.0)
I think these Magic-strings should be added tika-mimetypes.xml as well as
another PowerPoint mime-type. (maybe application/vnd.ms-powerpoint.2 or
application/vnd.ms-powerpoint.3 ?)
Example files in govdocs1:
144/144504.unk
272/272490.unk
430/430427.unk
(several more...)
2. Proprietary File Format: SigmaPlot Exchange File .jxf:
Magic: 0x8888000c4a5846
Example file in govdocs1:
975/975382.unk
975/975383.unk
(several more...)
3. Bitflip or valid Magic for application/vnd.ms-excel.sheet.2
In one file (376/376222.unk) I found
0x0900040007001000
instead of
0x0900040000001000
I guess the bit just flipped for any reason (interception of the data or sth.
else)
If the is might be recognized by any other files the magic for
application/vnd.ms-excel.sheet.2 should be adapted.
4. Special Header/Wrapper in front of application/vnd.ms-excel.sheet.3
In file 611/611703.unk I found a 128-byte long header in front of the excel
file.
therefore the file could not be recognized correclty by TIKA
After I cut the header, the file could be recognized and converted by TIKA.
Let me know if I should open a separate ticket for case 1.
If there is any better place (except the mailing lists) to publish the
analyzation results let me know.
Regards
Andreas
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