QuickTime 3 Reference
Two new functions allow you to get and set a portion of a preloaded track. There is also a new function for working with modifier tracks.
The SetTrackLoadSettings function allows you to specify a portion of a track that is to be loaded into memory whenever it is played.
pascal void SetTrackLoadSettings (Track theTrack, TimeValue preloadTime, TimeValue
preloadDuration, long preloadFlags, long defaultHints);
The SetTrackLoadSettings allows you to control how the Movie Toolbox preloads the tracks in your movie. By using these settings, you make this information part of the movie, so that the preloading takes place every time the movie is opened, without an application having to call the LoadTrackIntoRAM function. Consequently, you should use this feature carefully, so that your movies do not consume large amounts of memory when opened.
The Movie Toolbox transfers this preload information when you call the CopyTrackSettings function. In addition, the preload information is preserved when you save or flatten a movie (using either the FlattenMovie or FlattenMovieData functions). In flattened movies, the tracks that are to be preloaded are stored at the start of the movie, rather than being interleaved with the rest of the movie data. This improves preload performance.
The GetTrackLoadSettings function allows you to retrieve a track's preload information.
pascal void GetTrackLoadSettings (Track theTrack, TimeValue *preloadTime, TimeValue
*preloadDuration, long *preloadFlags, long *defaultHints);
The GetTrackDisplayMatrix function returns a matrix which is the concatenation of all matrices currently effecting the track's location, scaling, and so on. This includes the movie's matrix, the track's matrix, and the modifier matrix. Since modifier information is passed between tracks at MoviesTask time, the information returned by this call will represent the matrix in effect at the last MoviesTask call.
pascal OSErr GetTrackDisplayMatrix(
Track theTrack,
MatrixRecord *matrix );
To determine the entire clip of a track at the current time using GetTrackDisplayBoundsRgn . The results of GetTrackDisplayBoundsRgn take into account any clip regions provided by modifier tracks.