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To: tiff@sgi.com
From: bl@ppc.mc (bruno Ledoux)
Subject: Re: Reading concatenated tiff files
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Hi,

Storing multiple images in a TIFF file not discouraged at all, and works
very well (we currently use it to store multiple resolution of the same
scanned image in one file).
To acces one specific image we do the following:
     ...
     // Open tiff file in a standard way.
     tif = TIFFOpen("file","r");
     // Set the tiff directory you wan't to access
     // (res ranges from 0 to number of image minus one)
     TIFFSetDirectory(tif,(tdir_t)res);
     // Read whatever you want in current image.
     TIFFGetField(...);
     ...
Hope this helps,

Bruno,

>I'm thinking about using concatenated tiff files as a simple movie
>format for visualisation. I am testing the feasability at the moment
>using libtiff-v3.4beta031 , but I am having trouble reading the second
>image. My plan was to open the file, read the first tiff, and then parse
>for the header of the second file, and then call TIFFFdOpen again. This
>process doesn't seem to work. I'm reasonably confident that the parser
>is doing the correct thing, and I suspect that the TIFF i/o routines are
>reseting the file descriptors to the start of the file. (The error
>message is "Can not read TIFF directory.")
>
>If I place a couple of spaces at the start of the file, seek past them,
>and then try to call TIFFFdOpen, I also get errors.
>
>Is there some other technique I could be using? Is this approach
>intended to be discouraged by the tiff library?
>I know that tiff supports multiple images, and I intended to support
>that option later. The concatenated file was just meant to be an easily
>created format.
>
>Any advice appreciated.
>
>--
>Richard Beare
>Richard.Beare@cmis.csiro.au

 ----------------------------------------------------------
            Bruno LEDOUX
            PPC Multimedia, 7 rue du Gabian  98000 MONACO
            http://www.ppc.mc
            tel.: (+377) 97 98 41 60
            fax : (+377) 97 98 41 61


