Protecting QuickTime Movies for Projector Use Only

Date:    Sun, 4 Jun 1995 10:59:02 -0500
From:    Gretchen Macdowall <gcm@TIAC.NET>
Subject: Quicktime Question- a good one!

< Can you use lingo to alter a quicktime movie to play only in a projector
< and be rendereded useless outside the projector?
If you want to use fileIO you can. I'd do a lot of experimenting on test movies with this before I implemented it but you can:
  1. Flatten the movie so it's the same file on Mac and PC
  2. Open it as "read" with fileIO
  3. Read in the first 20 characters and store the character position and character value of only those characters with a value greater than 0. I stored them in a field in the Director movie.
  4. Close it and open it again as "append"
  5. Use mSetPosition to replace each non-0 character you found with "*"

This has effectively trashed the few QT's I tried it with enough to make MoviePlayer not play them.

To restore the QT, open it again as "append" and use your stored record of the character positions and values to write the right characters back in. Voila - a functioning QT.

You could distribute the trashed QT movies with your projector, restore them at startup from data you have stored in a Director field, and trash them again on closing your projector. Naturally this would not work on QT on a CD since you wouldn't be able to modify the files.