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

GlossaryNational Television System Committee(NTSC) Refers to the color-encoding methodadopted by the committee in 1953. This standardwas the first monochrome-compatible, simultaneouscolor transmission system used for publicbroadcasting. This method is used widely in theUnited States.node Either a panorama or an object in aQuickTime VR movie.NTSC See National Television System Committee.object track A track in a QuickTime VR movie thatcontains a set of views of a VR object.offset-binary encoding A method of digitallyencoding sound that represents the range ofamplitude values as an unsigned number, with themidpoint of the range representing silence. Forexample, an 8-bit sound sample stored inoffset-binary format would contain sample valuesranging from 0 to 255, with a value of 128 specifyingsilence (no amplitude). Samples in Macintosh soundresources are stored in offset-binary form. Comparetwos-complement encoding.PAL See Phase Alternation Line (PAL).packet For uncompressed audio, a sample from asingle channel. For compressed audio, this field hasno real meaning; by convention, it is treated as1/number-of-channels.panorama A structure of QuickTime VR data thatforms a virtual-world environment within which theuser can navigate.panorama track A track in a QuickTime VR moviethat contains a panorama.Phase Alternation Line (PAL) A color-encodingsystem used widely in Europe, in which one of thesubcarrier phases derived from the color burst isinverted in phase from one line to the next. Thistechnique minimizes hue errors that may resultduring color video transmission. Sometimes calledPhase Alternating Line.playback quality A relative measure of the fidelityof a track in a QuickTime movie. You can control theplayback (or language) quality of a movie duringmovie playback. QuickTime chooses tracks fromalternate tracks that most closely correspond to thedisplay quality desired. See also alternate track.poster A frame shot from a movie, used torepresent its content to the user.preferred rate The default playback rate for aQuickTime movie.preferred volume The default sound volume fora QuickTime movie.preview A short, potentially dynamic, visualrepresentation of the contents of a file. The StandardFile Package can use previews in file dialog boxesto give the user a visual cue about a file’s contents.See also file preview.preview atom An atom of type 'pnot', which canappear in a QuickTime file to contain a movie’s filepreview.profile atom An atom of type 'prfl', whichsummarizes the features of a movie or track.property Information about a sprite that describesits location or appearance. One sprite property is itsimage, the original bitmapped graphic of the sprite.parent atom A QT atom that contains other QTatoms, which are its child atoms. See also child atom.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.441