giant@lindy.Stanford.EDU (Buc Richards) (06/07/90)
Many of the TIFF files stored on the NeXT library, particularly those in the Webster Dictionary pictures file, appear to have a non-standard TIFF format. In particular, the Compression tag field has the value 32766 (7ffe hex), although the only legal values listed in the Version 5.0 TIFF description are 1, 2, 5, and 32773. I suppose that this is a special NeXT extension appropriate for compressing 2-bit gray-scale images. I also imagine that this is the reason that the Icon app refuses to open such tiff files, claiming that they are "Unsupported TIFF". Can I get a description of this TIFF extension and the associated compression scheme? Thanks. Buc Richards AIR Stanford University
wjs@fred.cs.washington.edu (William Shipley) (06/07/90)
giant@lindy.Stanford.EDU (Buc Richards) writes: >Many of the TIFF files stored on the NeXT library, particularly those >in the Webster Dictionary pictures file, appear to have a non-standard >TIFF format. >Can I get a description of this TIFF extension and the associated >compression scheme? Probably not. Imagine that you were Webster, and NeXT asked you if they could take all your pictures and digitize them. What would you say? "Sure, but encode them so they aren't any good on any other machine." Note: This is my guess, but it's an educated guess. I've seen this question asked before, and I've never seen it answered. NeXT has been real good about providing people with info they want them to have, so I'm assuming they have a reason for not providing that format. -william shipley
eps@toaster.SFSU.EDU (Eric P. Scott) (06/08/90)
In article <12181@june.cs.washington.edu> wjs@last.cac.washington.edu (William Shipley) writes: >giant@lindy.Stanford.EDU (Buc Richards) writes: >>Can I get a description of this TIFF extension and the associated >>compression scheme? > >Probably not. BZZZ! WRONG! > Imagine that you were Webster, and NeXT asked you if they >could take all your pictures and digitize them. What would you say? >"Sure, but encode them so they aren't any good on any other machine." > >Note: This is my guess, but it's an educated guess. I've seen this question >asked before, and I've never seen it answered. You must not have been paying attention a few months back. In any case, version 2.2 of Sam Leffler's tiff package was released about 3 days ago, so you'll probably want to grab it even if you had one of the earlier versions. FTP ucbvax.berkeley.edu:pub/tiff/v2.2.tar.Z and extract libtiff/tif_next.c--the encoding turns out to be quite simple. -=EPS=-
aozer@next.com (Ali Ozer) (06/08/90)
In article <9865@lindy.Stanford.EDU> Buc Richards writes: >Many of the TIFF files stored on the NeXT library, particularly those >in the Webster Dictionary pictures file, appear to have a non-standard >TIFF format. In particular, the Compression tag field has the value >32766 (7ffe hex), although the only legal values listed in the >Version 5.0 TIFF description are 1, 2, 5, and 32773. ... >Can I get a description of this TIFF extension and the associated >compression scheme? You're right --- Those files are compressed with a non-standard compression scheme... If you wish to be able to make just several of those into standard TIFFs, go ahead and screen capture them with Icon, which will then save them using no compression. If you really want to be able to read a lot of them, then I recommend getting a hold of Sam Leffler's wonderful TIFF library and using his "tiffcp" to fix up those files. Version 2.2 of the library is available from ucbvax.berkeley.edu. It compiles and runs on the NeXT just fine. Ali (Ali_Ozer@NeXT.com)
pvo@sapphire.OCE.ORST.EDU (Paul O'Neill) (06/08/90)
In article <12181@june.cs.washington.edu> wjs@last.cac.washington.edu (William Shipley) writes: >giant@lindy.Stanford.EDU (Buc Richards) writes: >>Many of the TIFF files stored on the NeXT library, particularly those >>in the Webster Dictionary pictures file, appear to have a non-standard >>TIFF format. > >>Can I get a description of this TIFF extension and the associated >>compression scheme? > >Probably not. .... I've seen this question asked before, and I've never >seen it answered. Get Sam Leffler's tiff library from ucbvax.berkeley.edu. It understands the NeXT compression. Paul O'Neill pvo@oce.orst.edu DoD 000006 Coastal Imaging Lab OSU--Oceanography Corvallis, OR 97331 503-737-3251