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

Some Useful Examples and ScenariosCreating a Timecode Track for 29.97 FPS VideoAtom sizeAtom typeVersion/FlagsSample sizeNumber of entriesAtom sizeAtom typeVersion/FlagsNumber of entriesOffset [1]20'stsz' (sample size)04120'stco' (chunk offset)01(offset into file of chunk 1)In the example, let’s assume that the segment’s beginning timecode is 1:15:32.4 (1 hour, 15 minutes, 32 seconds,and 4 frames). The time would be expressed in the data file as 0x010F2004 (0x01 = 1 hour; 0x0F = 15 minutes;0x20 = 32 seconds; 0x04 = 4 frames).The video and sound tracks must contain a track reference atom to indicate that they reference this timecodetrack. The track reference is the same for both and is contained in the track atom (at the same level as the trackheader and media atoms).This track reference would contain the data values listed in Table 6-4 (page 355).Table 6-4Example track reference data valuesFieldAtom sizeAtom typeReference typeTrack ID of referenced track (timecode track)Value12'tref''tmcd'3In this example, the video and sound tracks are tracks 1 and 2. The timecode track is track 3.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.355