NSIsNotNil Configure subtitle tracks Selection Behavior. These settings affect which tracks will be added to the subtitle tracks list, and the settings used for each track. NSIsNotNil NSIsNotNil Subtitle tracks list. Track selection behavior and settings are loaded from the selected preset, and may be configured using the subtitle Selection Behavior dialog. HBIsoLanguageTrasformer SRT Offset. Positive or negative offset in milliseconds (ms) for the selected SRT format source track. Not applicable to other formats. NSIsNotNil