The time at which to start playback. This value is a ltmmDVD_HMSF_TIMECODE structure. Refer to the MSDN link below for more information.
SMPTE timecode, more properly known as SMPTE time and control code, is a series of digital frame address values, flags and additional data applied to a video or audio stream, and is defined in ANSI/SMPTE 12-1986. Its purpose is to provide a machine-readable address for video and audio. These are usually measured in seconds and they measure the time elapsed from the beginning of the file. It is a term describing the number you see on the VCR while you are playing a tape.
The portion of the file holding the audio data. The audio data might be compressed to save disk space. The data has to be decompressed using an audio decompressor before you can play (hear) it.