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

Movie AtomsSample AtomsFigure 2-48 (page 112) shows the layout of the sample size atom.Figure 2-48The layout of a sample size atomBytesSample size atomAtom sizeType = 'stsz'VersionFlags4413Sample size 4Number of entriesSample size table4VariableThe sample size atom contains the following data elements.SizeA 32-bit integer that specifies the number of bytes in this sample size atom.TypeA 32-bit integer that identifies the atom type; this field must be set to 'stsz'.VersionA 1-byte specification of the version of this sample size atom.FlagsA 3-byte space for sample size flags. Set this field to 0.Sample sizeA 32-bit integer specifying the sample size. If all the samples are the same size, this field contains thatsize value. If this field is set to 0, then the samples have different sizes, and those sizes are stored in thesample size table.Number of entriesA 32-bit integer containing the count of entries in the sample size table.Sample size tableA table containing the sample size information. The sample size table contains an entry for every samplein the media’s data stream. Each table entry contains a size field. The size field contains the size, in bytes,of the sample in question. The table is indexed by sample number—the first entry corresponds to thefirst sample, the second entry is for the second sample, and so on.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.112