1997.05.02 09:17 "Re: BIG TIFF file problems", by Bjorn Brox
I am having problems with very large tiff files created by our RIP software.
The tiff file created is a bilevel tiff comprising of uncompressed data in a single strip!! The size of the file is 707,953,939 bytes.
# tiffcp -s -c lzw a1.tif a1c.tif
a1.tif: Warning, incorrect count for field "StripOffsets" (1, expecting
111); tag ignored.
This error message is correct, see below:
I have a theory as to why this is happening:
Looking at a tiffdump of the file:
# tiffdump a1.tif
I noticed that the width (85640) multiplied by the height (66133) (=5,663,630,120) exceeds the maximum possible value of the type uint32 which is 4,294,967,295. It is this 'overflow' that causes tiffcp to fail!
The file tells: RowsPerStrip 597.
This means that there have to be (ImageLength + ImageLength - 1)/RowsPerStrip StripOffset and StripByteCounts values too, i.e. 111.
I am wondering if anyone agrees with my theory.
Well, you migth also get these kinds of errors, but by dividing the file into strips this error can be avoided.
Bjorn Brox, mailto:firstname.lastname@example.org, CORENA A/S, http://www.corena.no/
P.O.Box 1024, Kongsberg Naeringspark, N-3601 Kongsberg, NORWAY
Phone: +47 32 73 74 35, Fax: +47 32 73 68 77, Mobile: +47 92 63 85 90