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

Media Data Atom TypesMovie MediaNote When the duration of the embedded movie’s sample is adjusted, by default no other tracks are adjusted. Thiscan cause the overall temporal composition to change in unintended ways. To maintain the complete temporalcomposition, a higher-level data structure which describes the temporal relationships between the various tracks mustalso be included with the movie.kMovieMediaAutoPlayA Boolean that indicates whether or not the embedded movie should start playing immediately afterbeing instantiated. This atom is only used if the TimeBase of the embedded movie is not slaved to theparent movie. See the kMovieMediaSlaveTime atom in “Movie Media Sample Format” (page 310) formore information. If auto play is requested, the movie will be played at its preferred rate after beinginstantiated. If this atom is not present, the embedded movie will not automatically play.kMovieMediaLoopA UInt8 that indicates how the embedded movie should loop. This atom is only used if the TimeBaseof the embedded movie is not slaved to the parent movie. See the kMovieMediaSlaveTime atom in“Movie Media Sample Format” (page 310) for more information. If this atom contains a 0, or if this atomis not present, the embedded movie will not loop. If this atom contains a value of 1, the embedded movieloops normally—that is, when it reaches the end it loops back to the beginning. If this atom contains avalue of 2, the embedded movie uses palindromic looping. All other values are reserved.kMovieMediaUseMIMETypeText (not a C string or a pascal string) that indicates the MIME type of the movie import component thatshould be used to instantiate this media. This is useful in cases where the data reference may not containMIME type information. If this atom is not present, the MIME type of the data reference as determinedat instantiation time is used. This atom is intended to allow content creators a method for working aroundMIME type binding problems. It should not typically be required, and should not be included in moviemedia samples by default.kMovieMediaTitleCurrently unused. It would contain text indicating the name of the embedded movie.kMovieMediaAltTextText (not a C string or a pascal string) that is displayed to the user when the embedded movie is beinginstantiated or if the embedded movie cannot be instantiated. If this atom is not present, the name ofthe data reference (typically the file name) is used.kMovieMediaClipBeginA MovieMediaTimeRecord that indicates the time of the embedded movie that should be used. Theclip begin atom provides a way to specify that a portion of the beginning of the embedded movie shouldnot be used. If this atom is not present, the beginning of the embedded movie is not changed. Note thatthis atom does not change the time at which the embedded movie begins playing in the parent movie’s2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.312