2007.12.17 09:29 "[Tiff] Large file support in libtiff 3.8.2", by Jannes Bolten

2007.12.17 16:05 "Re: [Tiff] Large file support in libtiff 3.8.2", by Jannes Bolten

thanks for that.

i have read about the BigTiff effort. it's included in the alpha release of version 4.0, right? it's not what i need tho. my files are definitely under 4GB, but often more than 2GB.

i'm running OS X Leopard. i have installed the most recent release of libtiff (3.8.2) using MacPorts. if i understand you correctly, on my system i don't have to do anything to enable large file support?

my issue with Enblend (the software that it's all about for me) is that large TIFFs (2.42GB in 16-bit) are created without any problems. but Photoshop won't open them. my work-around is to use NIP2, a front end for VIPS. it is created specifically to work with very large files (larger than installed RAM). NIP2 always manages to open them. i then use NIP2 to save the image as a new file (TIFF also). the NIP2 generated TIFF is never an issue for Photoshop. (but it is typically smaller than the original, because i typically use NIP2 to delete an Alpha channel from the TIFF, and sometimes some cropping.)

Enblend's author tells me that the Enblend binary i've used was probably compiled using a libtiff without large file support. he says he suspects that's the reason Photoshop wouldn't recognize the TIFF created by Enblend. he recommended that i compile myself and make sure large file support is enabled.

but the guy who provided the broken Enblend i was using most probably created the OS X binary using his own OS X (unix type system). this would imply that he built it with a libtiff that has large file support by default.

starting what version was large file support enabled by default in OS X environments? (or has it always been supported for OS X?)


----- Original Message ----
From: Bob Friesenhahn <bfriesen@simple.dallas.tx.us>
To: Jannes Bolten <jannesbolten@yahoo.co.uk>
Cc: tiff@lists.maptools.org

Sent: Monday, December 17, 2007 4:06:51 PM

Subject: Re: [Tiff] Large file support in libtiff 3.8.2

I want to compile a program called Enblend on my system. My purpose is to have it blend images of over 300 mega pixels. The author of Enblends says that for that to work, my libtiff must be compiled with large file support.

Is large file support enabled by default, or does the configure script require specific options for large file support to be enabled?

If so, what are they? Couldn't find anything in the documentation with the source code.

Large file support is operating system dependent. Some operating systems don't have special large file support since large files are supported by default. Others require special build options. For Unix type targets, the configure script arranges to build libtiff with large file support by default. For Windows, it seems that the availability of large file support may depend on if you choose the Windows I/O interface or the POSIX I/O interface (I don't know the details).

The TIFF format itself maxes out at 4GB. There is a BigTIFF format supported by the development version of libtiff 4.0 which supports truely huge files but it seems to me that this development version is not completely usable yet since it does not even pass its own basic sanity checks.