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<h2>Canon CRW files: Mapping of CIFF to Exif tags</h2>
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<p> CRW files are encoded in CIFF format. CIFF format consists of a
header and a hierarchy of directories and entries, similar to TIFF
(but easier to deal with). In Exiv2, there is no CRW or CIFF type of
metadata. Instead, known and suitable CIFF tags are mapped to Exif
metadata, but not all CIFF tags are mapped. Exiv2 reads Canon CRW
files, parses the CIFF structure and maps known and suitable tags to
Exif metadata. Writing to CRW files entails a reverse mapping from
Exif metadata to the CIFF tags. This way it is possible, e.g., to
adjust the date when the image was taken by reading the CRW file,
modifying Exif.Photo.DateTimeOriginal and writing the Exif data back
to a CRW file. Tags for which there is no mapping defined are ignored
during both, reading and writing.</p>

<p>Reference: <a href="http://www.sno.phy.queensu.ca/~phil/exiftool/canon_raw.html">The Canon RAW (CRW) File Format</a> by Phil Harvey.</p>

<p>Exiv2 supports the mappings listed in the table below.</p> 
<p>Click on a column header to sort the table.</p>

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