Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Functions That Modify Movie Properties / Working With Movie User Data

GetTrackUserData

The GetTrackUserData function allows your application to obtain access to a track's user data list. You can then use the GetUserData, AddUserData, and RemoveUserData functions (described on page 2-219, page 2-219, and page 2-220, respectively) to manipulate the contents of the user data list. If the data list contains text data, you can use the GetUserDataText, AddUserDataText, and RemoveUserDataText functions (described on page 2-221, page 2-220, and page 2-222, respectively) to work with its contents.

pascal UserData GetTrackUserData (Track theTrack);

theTrack

Specifies the track for this operation. Your application obtains this track identifier from such Movie Toolbox functions as NewMovieTrack and GetMovieTrack (described on page 2-136 and page 2-188, respectively).

DESCRIPTION

The GetTrackUserData function returns a reference to the track's user data list. This reference is valid until you dispose of the track. When you save the track, the Movie Toolbox saves the user data as well. If the function could not locate the track's user data, it sets this returned value to nil.

ERROR CODES

invalidTrack

-2009

This track is corrupted or invalid

Memory Manager errors

SEE ALSO

You can use the GetMediaUserData function to gain access to a media's user data (described on page 2-217). Similarly, you can use the GetMovieUserData function (described on page 2-215) to work with a movie's user data.