Track Matte Atoms

QuickTime Movie File Format Specification, May 1996

Track Matte Atoms

Track matte atoms are used to visually blend the track's image when it is displayed. For a complete description on the use of mattes in QuickTime, see Inside Macintosh: QuickTime. Track matte atoms have an atom type value of 'matt' .

Figure 0-12 shows the layout of a track matte atom.

Figure 12 The layout of a track matte atom

Track matte atoms contain the following data elements.

Size: A 32-bit integer that specifies the number of bytes in this track matte atom.
Type: A 32-bit integer that identifies the atom type; this field must be set to 'matt' .
Compressed matte atom: The actual matte data in a compressed matte atom. These atoms are described in the next section.