Represents the "S" entry of the media offset 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:.

• T
• F
• M

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 285, page 501.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 296, page 627.

The S entry names the offset subtype: T for a time value in seconds, F for a frame number, or M for a named marker in the media file. The subtype determines which additional entry holds the actual offset value.