=== Granule Position ===
The granule position of an audio page encodes the total number of PCM samples in the stream up to and including the last fully-decodable sample from the last packet ''completed'' on that page. A page that is entirely spanned by a single packet (that completes on a subsequent page) has no granule position, and the granule position field
SHOULD be set to the special value ’-1’ in two's complement.
The granule position of an audio page is in units of PCM audio samples at a fixed rate of 48 kHz (per channel; a stereo stream’s granule position does not increment at twice the speed of a mono stream). It is possible to run a decoder at other sampling rates, but the format and this specification always count samples assuming a 48 kHz decoding rate.