Parse a seeking query, writing the format into format, and other results into the passed parameters, if the respective
parameters are non-null
| this |
a GST_QUERY_SEEKING type query Query |
| format |
the format to set for the |
| seekable |
the seekable flag to set, or null |
| segment_start |
the segment_start to set, or null |
| segment_end |
the segment_end to set, or null |