Bug 20070

Summary: The entry for IFF/ILBM is incomplete and somewhat confused
Product: shared-mime-info Reporter: Magnus Bergman <magnus.bergman>
Component: freedesktop.org.xmlAssignee: Shared Mime Info group <shared_mime_info>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: medium    
Version: unspecified   
Hardware: All   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments: ...and the patch
Fix the issue and add IFF super-type
image/x-ilbm test file
audio/x-aiff test file

Description Magnus Bergman 2009-02-11 12:25:52 UTC 
Created attachment 22836 [details] [review]
...and the patch

ILBM is one subtype of IFF (Interchange File Format) that contains images (like AIFF is an IFF file containing audio). Or actually it is two image formats (and this is a bit confusing): The first format has the IFF-type ILBM (InterLeaved Bitmap), is mostly used on Amiga computers and usually has the extension "iff" (or sometimes "ilbm"). The second format has the IFF-type PBM (not to be confused with Portable BitMap images), is used on PC and usually has the extension "lbm" (because earlier versiones of FAT didn't let it be "ilbm").

But I can't imagine that anybody cares that this is two different formats so they should probably be merged into one called simply "ILBM image" (even though this is incorrect since the ones commonly used on PC are not actually interleaved). This means ditching the type "IFF image" (which actually are the interleaved ones) and merging it with "ILBM image".

Perhaps there should be an IFF super type for completeness. IFF files are somewhat like binary XML-files that contains a tree of chunks. They where at least until reasently used by Electronic Arts (the original inventor of the format) in games, but not for audio or images but rather for game-specific data (like animation mappings for The Sims).
Comment 1 Bastien Nocera 2009-02-21 06:11:00 UTC 
Could you please add the super-type and some comments to explain the formats in the xml file?
Comment 2 Magnus Bergman 2009-02-22 15:52:24 UTC 
Created attachment 23181 [details] [review]
Fix the issue and add IFF super-type

An updated patch which also includes the application/x-iff super type. The types image/x-ilbm, audio/x-aifc and audio/x-aiff are made sub-classas of application/x-iff. (It also fixes some minor issues with the two audio types.)

I wasn't sure how to set the priority of the magic patterns, so perhaps I got it wrong. Neither was I sure how to create tests and such.
Comment 3 Magnus Bergman 2009-02-22 15:59:14 UTC 
Created attachment 23182 [details]
image/x-ilbm test file

A test ILBM image (of the PBM variant described above) created with Deluxe Paint for DOS. (Deluxe Paint is made by Electronic Arts who invented the IFF and ILBM formats).
Comment 4 Magnus Bergman 2009-02-22 16:03:24 UTC 
Created attachment 23183 [details]
audio/x-aiff test file

A test AIFF audio file (plain uncompressed AIFF) created with sox.
Comment 5 Bastien Nocera 2013-02-13 10:50:19 UTC 
commit ef7b04cf111b290b235cb5cfc5ffec8c04296999
Author: Bastien Nocera <hadess@hadess.net>
Date:   Wed Feb 13 11:47:26 2013 +0100

    Add test cases for AIFF and ILBM mime-types
    
    https://bugs.freedesktop.org/show_bug.cgi?id=20070

commit f6785575008fd1d0699197110ee2b767301ebee1
Author: Magnus Bergman <magnusbe@algonet.se>
Date:   Sun Feb 22 15:52:00 2009 +0000

    Add IFF super-type
    
    And fix problems with sub-types, such as AIFF and ILBM file types.
    
    https://bugs.freedesktop.org/show_bug.cgi?id=20070

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.