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

Movie AtomsMedia AtomsThe base media information header atom contains the following data elements.SizeA 32-bit integer that specifies the number of bytes in this base media information header atom.TypeA 32-bit integer that identifies the atom type; this field must be set to 'gmhd'.Base media info atomSee “Base Media Info Atoms” (page 91).Text media information atomSee “Text Media Information Atom” (page 196).Base Media Info AtomsThe base media info atom, contained in the base media information header atom ('gmhd'), defines the media’scontrol information, including graphics mode and balance information.Figure 2-30 (page 91) shows the layout of the base media info atom.Figure 2-30The layout of a base media info atomBase media info atomAtom sizeType = 'gmin'VersionFlagsGraphics modeOpcolorBalanceReservedBytes44132622The base media info atom contains the following data elements.SizeA 32-bit integer that specifies the number of bytes in this base media info atom.TypeA 32-bit integer that identifies the atom type; this field must be set to 'gmin'.VersionA 1-byte specification of the version of this base media information header atom.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.91