[File] [PATCH] Magdir/iff AIFF audio *.aiff *.aif *.aff

[Christos Zoulas]

Committed, thanks!

christos

> On Jul 23, 2023, at 6:16 PM, Jörg Jenderek (GMX) <joerg.jen.der.ek at gmx.net> wrote:
> 
> Hello,
> 
> Some days ago i run Pirisoft ccleaner. Under item for file extension
> under registry cleaner i can scan for errors. There it complains
> about file name suffix AFF.
> 
> So i looked for such files on my systems. Some samples are audio files.
> In this session i will only consider such audio samples. When running
> file command version 5.44 on such audio samples i get an output like:
> 
> SCREAM.AFF:   IFF data, AIFF audio
> example.aiff: IFF data, AIFF audio
> ring_in.aif:  IFF data, AIFF audio
> 
> With option --extension only 3 byte sequence ??? is shown and with -i
> option audio/x-aiff is shown.
> 
> For comparison reason i also run the file format identification
> utility DROID ( See https://sourceforge.net/projects/droid/). It does
> recognize the samples. These are here described as "Audio Interchange
> File Format" by PUID fmt/414. Here 2 suffix AIFF/AIF are considered as
> valid, but AFF not (See EXTENSION_MISMATCH true in appended
> droid-aiff.csv.gz).
> 
> For comparison reason i run the file format identification utility
> TrID ( See https://mark0.net/soft-trid-e.html). All examples are
> described with low priority as "Generic IFF container" with
> mime type application/x-iff by iff-gen.trid.xml. The audio samples are
> described with highest priority as "AIFF Audio Interchange File Format"
> with mime type audio/x-aiff by audio-aiff.trid.xml. Here 3 suffix
> (AIF/AIFF/AFF) are listed (See appended trid-v-aiff.txt.gz).
> 
> TrID list the used file name extension and often with -v option the
> related URL pointing to used file format information. With the help
> of these tools i found a page about IFF and AIFF on file formats archive
> team. So this is now expressed inside Magdir/iff by additional comment
> lines like:
> 
> # URL:	http://fileformats.archiveteam.org/wiki/IFF
> #	http://fileformats.archiveteam.org/wiki/AIFF
> #	https://en.wikipedia.org/wiki/Audio_Interchange_File_Format
> # Reference:	http://mark0.net/download/triddefs_xml.7z
> #	defs/a/audio-aiff.trid.xml
> 
> The detection happens inside Magdir/iff by first looking for keyword
> FORM and then for AIFF. This looks like:
> 0	string		FORM		IFF data
> >8	string		AIFF		\b, AIFF audio
> !:mime	audio/x-aiff
> 
> On many sites also mime type audio/aiff is mentioned, but when i look at
> IANA there is such type not officially registered.  On Linux machines by
> shared mime database the other type is used. This is also shown by file
> command. So i mentioned it in comment line.
> 
> Often only 2 file name extensions (AIF/AIFF) are listed. On the new
> reference site also a third suffix AFF is listed. On the site you can
> also download such samples. It is not explained why but i assume that
> are for historical reasons. The file format apparently starts on Amiga
> systems and on Apple Macintosh computer systems. There the 4 byte suffix
> aiff could be used. Because of limitations of old FAT file systems on
> DOS only 3 byte suffix can be used. So in most cases here the suffix
> shrinks now to AIF. Apparently on such file systems also the other 3
> byte variant AFF is also used. So now all 3 possible file name suffix
> are expressed by additional line like:
> !:ext	aiff/aif/aff
> 
> After applying the above mentioned modifications by patch
> file-5.44-iff-aiff.diff then my samples are now described like before
> but with correct name suffix. This now then looks with option
> --extension like:
> 
> SCREAM.AFF:   aiff/aif/aff
> example.aiff: aiff/aif/aff
> ring_in.aif:  aiff/aif/aff
> 
> I hope my diff file can be applied in future version of file
> utility.
> 
> There is something to do. The suffix AFF is also used for other file
> formats. I will try to handle these in a future session.
> 
> With best wishes,
> Jörg Jenderek
> --
> Jörg Jenderek
> <droid-aiff.csv.gz><trid-v-aiff.txt.gz><file-5_44-iff-aiff_diff.DEFANGED-547><file-5_44-iff-aiff_diff_sig.DEFANGED-548>--
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