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

Media Data Atom TypesHint Sample Data FormatFieldReservedData reference indexHint track versionLast compatible hint track versionMax packet sizeAdditional data tableBytes62224variableField descriptionsSizeA 32-bit integer specifying the size of this sample description in bytes.Data formatA four-character code indicating the data format of the hint track samples. Only 'rtp ' is currentlydefined. Note that the fourth character in 'rtp ' is an ASCII blank space (0x20). Do not attempt topacketize data whose format you do not recognize.ReservedSix bytes that must be set to 0.Data reference indexThis field indirectly specifies where to find the hint track sample data. The data reference is a file orresource specified by the data reference atom ('dref') inside the data information atom ('dinf') ofthe hint track. The data information atom can contain a table of data references, and the data referenceindex is a 16-bit integer that tells you which entry in that table should be used. Normally, the hint trackhas a single data reference, and this index entry is set to 0.Hint track versionA 16-bit unsigned integer indicating the version of the hint track specification. This is currently set to 1.Last compatible hint track versionA 16-bit unsigned integer indicating the oldest hint track version with which this hint track isbackward-compatible. If your application understands the hint track version specified by this field, it canwork with this hint track.Max packet sizeA 32-bit integer indicating the packet size limit, in bytes, used when creating this hint track. The largestpacket generated by this hint track will be no larger than this limit.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.257