Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Functions That Modify Movie Properties / Working With Sound Volume

SetTrackVolume

The SetTrackVolume function allows your application to set a track's current volume.

pascal void SetTrackVolume (Track theTrack, short volume);

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).

volume

Specifies the current volume setting of the track represented as a 16-bit, fixed-point number. The high-order 8 bits contain the integer part of the value; the low-order 8 bits contain the fractional part. Volume values range from -1.0 to 1.0. Negative values play no sound but preserve the absolute value of the volume setting.

kFullVolume

Sets the track to full volume (constant value is 1.0).

kNoVolume

Sets the track to no volume (constant value is 0.0).

DESCRIPTION

Note that, when the track is played, the track's volume is scaled by the volume setting of the movie that contains the track.

ERROR CODES

invalidTrack

-2009

This track is corrupted or invalid

SEE ALSO

Your application can obtain the current volume setting by calling the GetTrackVolume function, which is described in the next section.