This box contains the sample dependencies for each switching sample. The
dependencies are stored in the table, one record for each sample. The size of
the table is taken from the the Sample Size Box ('stsz') or Compact Sample
Size Box ('stz2').

@author Alexander Simm

The dependency count is an integer that counts the number of samples
in the source track on which this switching sample directly depends.
return  all dependency counts

The relative sample number is an integer that identifies a sample in
the source track. The relative sample numbers are encoded as follows.
If there is a sample in the source track with the same decoding time,
it has a relative sample number of 0. Whether or not this sample
exists, the sample in the source track which immediately precedes the
decoding time of the switching sample has relative sample number –1,
the sample before that –2, and so on. Similarly, the sample in the
source track which immediately follows the decoding time of the
switching sample has relative sample number +1, the sample after that
+2, and so on.

@return all relative sample numbers