Quicktime File Format (2012-08-14).pdf

Movie AtomsTrack AtomsNote Figure 2-6 (page 56) contains an optional track profile atom ‘prfl’. Track profile atoms aredeprecated in the current version of QuickTime but may be present in existing QuickTime files. Theinclusion here is intended to document existing content containing profile atoms, they should notbe used for new development.Figure 2-6The layout of a track atomTrack atomAtom sizeType = 'trak'Profile atom'prfl'Track header atom 'tkhd' ‡Track Aperture Mode Dimensions atomClipping atomTrack matte atomEdit atomTrack reference atomTrack exclude from autoselection atomTrack loading settings atomTrack input map atomMedia atomUser data atom'tapt''clip''matt''edts''tref''txas''load''imap''mdia' ‡'udta'‡ Required atomTrack atoms contain the following data elements.SizeA 32-bit integer that specifies the number of bytes in this track atom.TypeA 32-bit integer that identifies the atom type; this field must be set to 'trak'.Track profile atomSee “Track Profile Atom” (page 57) for details.Track header atomSee “Track Header Atoms” (page 57) for details.Track aperture mode dimensions atomSee “Track Aperture Mode Dimension Atoms” (page 61) for details.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.56