Represents the "S" entry of the media duration dictionary object.

It is a required entry defined as part of the PDF 1.0 specification.

It contains a string representing a PDF name object.

This item may take one of the following valid values:.

• I
• F
• T

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 281, page 498.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 292, page 623.

The S entry names the duration subtype: I for intrinsic duration (play the full clip), or T for a specified time duration given by the T entry. Intrinsic duration uses the media file natural length.