alice-teacher Alice tips: problems exporting Alice animations to .mov files

Don Slater dslater at andrew.cmu.edu
Mon Oct 25 08:36:58 EDT 2010


A question we often receive:

"We sometimes have difficulty exporting Alice files to movie (.MOV format). Sometimes it just fails, sometimes it cuts random parts, sometimes it clips the end of the movie off… Is this a known issue? Any tricks to this process?"

--- Response from Wanda Dann --- 

Export to movie has been "hit & miss"  -- mostly because of problems with sound files not being easily integrated.

Sound files need to be clipped to be the length actually played in the animation.

For example, if a sound file is 1.5 minutes long but only 20 seconds is being played in the animation, Alice still loads the entire sound file, but the underlying operating system does not release the sound process when the animation finishes. (Alice has a hard time recognizing when an animation is over.)

The end result is that when Quicktime is trying to record the captured video with the sound file, it is denied access to the sound file because the sound file is still open.
This causes the whole process to go out of whack.

The best fix is to edit the sound clip to the actual length of the animation. Then when it is finished playing it is released.  This allows Quicktime access to the file during the recording phase.

We have always recommended Audacity as a good open source sound editor, but there are other tools out there that will work as well.

---

Any other thoughts / comments / questions?


Don Slater




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