I thought all midis were the same until I started working on my own ringtone site. I have since discovered that while the file ending is .mid they do not always share the same mime type. I know how to use php to open the file but I have no idea what to check for inside the file to tell what kind of file they are. Any help on this matter would be greatly appreciated.

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Here is the site if you want to look at it:
http://fatfreewater.com/midi/l2.php
audio/midi is the mime type I'm using for all midi's but not all files work. Some of them return the "905 Attribute Mismatch" while others work fine.
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