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google-code-export / thebigpicture

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IPTC should implement extended tags #20

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
IPTC records have twqo kind of tags; normal and extended. Normal tags are
used if the data fits into 32767 bytes, extended is used otherwise. They
can be distinguished by reading the most significant bit; 0 menas normal, 1
means extended.

In case of an extended tag, the length parameter does not specify the
length of the data, but the number of bytes that specify the length of the
data:

Normal tag:
Unique (1) - Record num (1) - Tag num (1) - Data length (2) - Data (data
length)

Extended tag:
Unique (1) - Record num (1) - Tag num (1) - Data length length (2) - Data
length (data length length) - Data (data length)

Original issue reported on code.google.com by p.edel...@gmail.com on 19 Mar 2007 at 9:45

GoogleCodeExporter commented 9 years ago 
Resolved in revision 21, although technically it cannot decode or encode more 
than 2
** 32 bytes. This is over 4 gigabyte, and should be more than we ever need in 
IPTC/NAA.

Closing issue.

Original comment by p.edel...@gmail.com on 19 Mar 2007 at 11:20