best way to determine (MIME) content type of a stream of bytes?

  hi, i'm interested in the most comprehensive way to determine the
content type of a stream of bytes that's been uploaded to a PHP
script?  assuming that the bytes are uploaded simply via a POST
parameter, i can see that there are a couple ways to do it:

  * getimagesize()
  * FileInfo

i've been doing some testing this morning and a few video formats
handed to FileInfo come back as "application/octet-stream" which isn't
particularly informative.  and i want to support as many different
formats of image, audio and video as possible.

  so ... what's the best way?  oh, by the way, when i used fileinfo, i
didn't bother handing over a magic file.  i'm starting to think that
would make a difference.  and is there a noticeable advantage to
upgrading to PHP 5.3 since the server (centos 5.4) is currently
running only PHP 5.1.6.  thanks.

rday
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Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
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