1Image::ExifTool::AFCP(3U)ser Contributed Perl DocumentatiIomnage::ExifTool::AFCP(3)
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6 Image::ExifTool::AFCP - Read/write AFCP trailer
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9 This module is used by Image::ExifTool
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12 This module contains definitions required by Image::ExifTool to extract
13 information from the AFCP trailer. Although the AFCP specification is
14 compatible with various file formats, ExifTool currently only processes
15 AFCP in JPEG images.
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18 AFCP is a specification which allows meta information (including IPTC)
19 to be appended to the end of a file.
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21 It is a poorly designed protocol because (like TIFF) it uses absolute
22 offsets to specify data locations. This is a huge blunder because it
23 makes the AFCP information dependent on the file length, so it is eas‐
24 ily invalidated by image editing software which doesn't recognize the
25 AFCP trailer to fix up these offsets when the file length changes.
26 ExifTool will attempt to fix these invalid offsets if possible.
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28 Scanning for AFCP information may be time consuming, especially when
29 reading from a sequential device, since the information is at the end
30 of the file. In these instances, the ExifTool FastScan option may be
31 used to disable scanning for AFCP information.
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34 Copyright 2003-2007, Phil Harvey (phil at owl.phy.queensu.ca)
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36 This library is free software; you can redistribute it and/or modify it
37 under the same terms as Perl itself.
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40 <http://www.tocarte.com/media/axs_afcp_spec.pdf>
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43 "AFCP Tags" in Image::ExifTool::TagNames, Image::ExifTool(3pm)
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47perl v5.8.8 2007-09-12 Image::ExifTool::AFCP(3)