EXS 24 Logic Sampler Users Group

At 10:36 AM 5/22/02 -0500, you wrote:
>Anders Elverhøy wrote:
>
> > Hi list!
> >
> > I've made a percussion instrument for EXS-24.
> > It's royalty free and you can find it at
> > http://www.revolvermusic.no/sounddownload.htm
> >
>
>Hi Anders,
>
>I downloaded your file and the samples don't seem to show up as audio files
>(on Mac). And from what I can tell, it's not a matter of adding a file
>extension on or anything like that; they just don't seem to be audio files.

They are SoundDesigner 2 files, and the EXS file (without the extension) is 
OK. No problem.

This would be worthy of a Info page. Forgive any obvious info, and please 
correct me where I'm wrong; files on the Mac have three things to consider 
when you want to know "what" they are and what applications they work with. 
See below.

Files without an extension, and if they aren't typed (these were, though), 
can cause some confusion what they are. That's the beauty of the Windows 
system - the extensions show you visually what the files are, since you 
can't really depend on icons nor type codes for that information. (Of 
course, Bill Gates doesn't help it when his defaults try to emulate the 
Mac, re: "Hide File Extensions For Known File Types"...)

------------------------------------------------

The Extension
This is how Windows basically identifies files. An "extension" is 
classically defined as any number of characters after the last "dot." 
Examples: brass.exs, trumpet1.aif, explosion.wav

The FileType and Creator Code
Every file has a Type and Creator Code on a Mac. These are created when the 
file is made, at least on the Mac, or when they are changed, of course. 
Obviously, if a file is not created on a Mac, or is coming through a medium 
where this information is stripped out, you lose this information. But on a 
Mac every file has this information, so these files get some type of 
default. This information is in the File Exchange Control Panel.

You can run into severe problems if you have files coming in, being 
default-typed as described above, and you have you File Exchange set to 
interpret these files as TEXT. Big reason - depending on the application 
and circumstances, the file may get corrupted by the app or whatever 
replacing all the number 13 and 10 with just number 13. This is because on 
a Mac, the end of a line of a text file is denoted as just a "carriage 
return" - which is the number 13. On other systems, including Windows, it 
is denoted by a carriage return and a "end-of-line", which is the number 
10. So if anything is auto-translating the end of line characters, your 
nice file will be corrupted - unless it's a text file in the first place.

The Creator Code is supposed to be the code of the application that 
"created" it or the application that is "supposed to" open the file. It's 
not critical, and most apps don't care about it. It's helpful for the 
Finder to have an icon for it, though. You can see this when you download a 
.wav file from the web and open it and/or save it on an editor. First, the 
file didn't have a custom icon. Afterwards, it does - it's because the app 
put it's Creator Code on it.

The Type is the type of file it is, and that's the more critical thing. It 
determines if a file shows up, and if highlighted or not, in a Open dialog. 
It's one of the piece of information the system and applications use to 
know what type of file it is and what to do with it.

The Application
This is best explained by an example. The files mentioned above are 
SoundDesigner 2. I found that by two ways. First I dragged one and hovered 
over Peak. Peak lit up, like it was ready to receive it. So I dropped it, 
and the waveform appeared. The problem is - this didn't tell me what file 
type it was - I have an older version of Peak and I don't see any place 
this mentions this. So - I dragged it over Alchemy - but Alchemy didn't 
light up. This is because Alchemy doesn't take this file type as one it 
accepts for dragging. However, if I open Alchemy and select the file, it 
opens it fine (regard this as an Alchemy bug or defiecncy). And it said it 
was a stereo SoundDesigner file.

The other way is that I dragged a file on a cute app called FileTyper 
www.ugcs.caltech.edu/~dazuma/filetyper/ - it told me it's codes, which I 
recognized as SD.

What this all means is that the application is really the master at 
deciding what the file codes really MEAN. I mean, there are some sound data 
file types that are actually TEXT - but if you have an app that sees TEXT, 
and knows that once it receives it, that  it should do x and y and z with 
it, it's OK.

----------------------------------------

Since a file can be "typed" any sort of ways, and that that information is 
dubious based on the wide variety of places the file can come from, a good 
application will look at all of these things to determine what kind of file 
it is. Typically, the app should look at the File Type first, and see if 
that lines up with any extension the name has, It then should run a test on 
the headers to see if it's OK. If that isn't OK, the test should say what 
the file REALLY is, and then open it accordingly, or show an error message 
if appropriate.


Garth Hjelte
Sampler User