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

Movie AtomsSample AtomsSizeA 32-bit integer that specifies the number of bytes in this time-to-sample atom.TypeA 32-bit integer that identifies the atom type; this field must be set to 'stts'.VersionA 1-byte specification of the version of this time-to-sample atom.FlagsA 3-byte space for time-to-sample flags. Set this field to 0.Number of entriesA 32-bit integer containing the count of entries in the time-to-sample table.Time-to-sample tableA table that defines the duration of each sample in the media. Each table entry contains a count fieldand a duration field. The structure of the time-to-sample table is shown in Figure 2-36 (page 102).Figure 2-36The layout of a time-to-sample table entrySample countSample durationField4 4BytesYou define a time-to-sample table entry by specifying these fields:Sample countA 32-bit integer that specifies the number of consecutive samples that have the same duration.Sample durationA 32-bit integer that specifies the duration of each sample.Entries in the table describe samples according to their order in the media and their duration. If consecutivesamples have the same duration, a single table entry can be used to define more than one sample. In thesecases, the count field indicates the number of consecutive samples that have the same duration. For example,if a video media has a constant frame rate, this table would have one entry and the count would be equal tothe number of samples.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.102