Technical Q&A's

QTMTB 28 - Stepping Through QuickTime-Movie (1-May-95)

Q It is simple to step through QuickTime-movie video frames in the order they appear in the movie using GetMovieNextInterestingTime, except for getting the first frame. If I set the time to 0 and rate to 1, I get the second frame, not the first. In addition, the video may start later than at 0. What can I do to ensure that I start with the first video frame?

A To always get the first frame under the conditions you describe, you have to pass the flag nextTimeEdgeOK to GetMovieNextInterestingTime. The nextTimeEdgeOKflag makes the call return the current interesting time instead of the next interesting time, if the current time is an interesting time. You have to do this because there's no way to go below the first frame and then ask for the next interesting time.

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