mvGetTrackTimeScale(3dm)mvGetTrackTimeScale(3dm)NAME
mvGetMovieTimeScale, mvSetMovieTimeScale, mvGetTrackTimeScale,
mvSetTrackTimeScale - get and set a movie or track timescale.
SYNOPSIS
#include <dmedia/moviefile.h>
MVtimescale mvGetTrackTimeScale( MVid track );
DMstatus mvSetTrackTimeScale( MVid track, MVtimescale timeScale );
MVtimescale mvGetMovieTimeScale( MVid movie );
DMstatus mvSetMovieTimeScale( MVid track, MVtimescale timeScale );
DESCRIPTION
For information one how to interpret a time, timeScale pair, please see
the ``Time and Timescale'' section of mvIntro.
These function in the movie library are provided to allow the user to get
or set the default timescale for either a track or a movie.
TRACK TIMESCALE AND MOVIE TIMESCALE
mvGetTrackTimeScale allows the user to learn what timescale the movie
library is using internally to represent track edits. It allows an
application to know the finest resolution at which edits can be made to a
track without losing precision.
mvSetTrackTimeScale allows the user to set a track's time scale, although
most users will want not want to use this function and should use the
track time scale selected by the movie library. (If the user does not
call mvSetTrackTimeScale, the movie library will select a "reasonable"
track timescale based on the DM_IMAGE_RATE which was passed in to
mvAddTrack.) Furthermore, the only time that mvSetTrackTimeScale should
be called is immediately after a track has been created--before any data
has been added to the track or the track has been edited. Changing a
track's timescale after the track contains data will cause data loss.
mvGetMovieTimeScale is only needed by certain classes of applications
which are very knowledgeable about specifics of the file format of the
files which they are editing.
mvGetMovieTimeScale provides the application access to a timescale that
is associated with the entire movie. Due to the design of the
QuickTime(tm) file format, this is the finest editing resolution that can
be saved to disk as a QuickTime file, although for other file formats it
may be used for other purposes, or ignored.
mvSetMovieTimeScale allows the user to set this time scale. It is not
recommended that users set this time scale after a movie has been edited.
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mvGetTrackTimeScale(3dm)mvGetTrackTimeScale(3dm)
If the user does not set a movie time scale, the movie library will
automatically select a ``reasonable'' one.
RETURN VALUES
The set functions return either DM_SUCCESS or DM_FAILURE. The get
functions will return -1 on error (e.g., bad movie id).
NOTES
QuickTime is a registered trademark of Apple Computer, Inc.
SEE ALSOmvIntro(3dm), mvGetErrno(3dm).
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