Hello trid users,
some days ago i handle some genealogical database. One format used
filename extension ged. Unfortunately that suffix is also used for
other file formats. One such format is an Atari graphic.
So i run trid utility on my Atari GED examples. My graphic samples are
described as wrong with high priority as "Atari XE Executable" by
exe-xex.trid.xml. The samples are also described as "MP3 audio" by
audio-mp3.trid.xml. Some samples are described with low priority as
"Sybase iAnywhere database files" by sybase-ianywhere-dbf.trid.xml
(See appended output/trid-v-old.txt).
For comparison reason i also run file command (version 5.44) on such
samples. Here all graphic samples are also not recognized and are
described as "data". It also shows generic mime type
application/octet-stream (see appended output/file-i-5.44.txt) and no
file name suffix (see appended output/file-ext-5.44.txt).
For comparison reason i also run the file format identification
utility DROID ( See
https://sourceforge.net/projects/droid/). Here the
examples are also not recognized.
So i run tridscan on such GED samples to generate ged-atari.trid.xml.
Apparently all GED samples start with same 6 byte sequence. This is
expressed by first XML construct that looks like:
<Bytes>FFFF30534F7F</Bytes>
<ASCII> . . 0 S O</ASCII>
<Pos>0</Pos>
Luckily i found a Instead page about GED on file formats archive team
web site. This is now expressed by line like:
<RefURL>
http://fileformats.archiveteam.org/wiki/GED</RefURL>
There also samples to download are mentioned as link. There also a
link to software RECOIL that can show and convert such images is
listed. Then you can see resolution of graphic is always 160x200. When
converting to PNG this becomes 320x200. I do not know why. That
information is also visible on page with list of supported formats by
Recoil. See:
https://recoil.sourceforge.net/formats.htmlThere as suffix only GED is listed. That is expressed inside TrID
definition by line like:
<Ext>GED</Ext>
The file format is simple described as "GED" for Atari 8-bit
platform. So i take this as basis for TrID description by line like:
<FileType>Atari GED graphic</FileType>
When looking in source file recoil.c i see that file size apparently
is always 11302. So i also mention this in remark line. Unfortunately
i am no c programmer. So i do not understand the used file format. If
you are an experienced c-programmer you probably are able to
understand file format and are able to interpret patterns found by
tridscan. So i leave these pattern inside TrID. These looks like:
<Bytes>000000</Bytes>
<Pos>112</Pos>
...
<Bytes>1E1E1E1E1E1E1E1E1E1E1E1E</Bytes>
<Pos>394</Pos>
<Bytes>00000000000000000000000000000000000000000000000000000000</Bytes>
<Pos>2006</Pos>
The samples are just graphic images. So i apply an user defined mime
type. This type is expressed by line like:
<Mime>image/x-atari-ged</Mime>
With the new trid definitions now my Atari GED examples are described
(see appended output/trid-v-new.txt). TrID definitions and output are
stored in archive ged.zip. I hope that my definition can be used in
future version of triddefs.
With best wishes
Jörg Jenderek
