QTPC 10 - IMA 4:1 Codec Conflicts with Macintosh Easy Open Title Banner

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QTPC 10 - IMA 4:1 Codec Conflicts with Macintosh Easy Open (1-Aug-95)

Q There seems to be some sort of conflict between the QuickTime IMA 4:1 codec and Personal AppleShare. We have some AIFF audio files that are in the IMA 4:1 format (SoundConverter was used to generate them), and we play these files as if they were QuickTime files, using OpenMovieFile/NewMovieFromFile/StartMovie. Occasionally, on some machines, no sound is played, and error code -2048 is returned by NewMovieFromFile. This seems to happen whether the file was handled by QuickTime code or by SoundManager.

We have observed this on a Quadra 650 running System 7.1, a Centris 610 running System 7.5.1, a Quadra 840av running System 7.1, and a IIsi (system not known). The problem appears to be related to file sharing, since it disappears if the file sharing extension is not loaded or is switched off.

This problem is not reproducible on all Mac models -- on my Power Mac 7100/66av (running System 7.5), sound plays normally regardless of whether file sharing is on or off. We have also seen this problem on a Quadra 650 running System 7.5, but only intermittently.

Are there any known problems with QuickTime and Personal AppleShare?

A There are no known problems or conflicts with QuickTime and Personal AppleShare. However, we have been able to reproduce the behavior you describe, and we've determined that Macintosh Easy Open is causing the problem. If you turn off Macintosh Easy Open or change the creator type to match MoviePlayer, the problem disappears.

Having File Sharing turned on probably just aggravates Macintosh Easy Open, but it doesn't seem to have any other effect on QuickTime.

This is what we recommend: Turn off Macintosh Easy Open to determine if this solves the problem. If it does, modify your sound-file creator types to reference the direct application (this should eliminate the problem, even when Macintosh Easy Open is on). If you still have the problem, try converting the sound files into movie files (you can use MoviePlayer to do this).
If you want more information on working with Macintosh Easy Open, see Chapter 7 (Translation Manager) of Inside Mac: More Macintosh Toolbox. This volume of Inside Mac is available on the March '95 Developer CD at the following path:

Mar 95 Dev DC:Technical Documentation:Inside Macintosh:More Mac TB.

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