Which option is NOT necessary for specifying a default transition?

The option that is not necessary for specifying a default transition is editing the audio settings of the transition. When setting a default transition in a video editing application, the primary steps involve selecting a transition from the Video Transitions bin and indicating that it should be set as the default. This can be done through right-clicking or using the menu options in the Effects panel.

Editing the audio settings, while it can be important for individual transitions, is not required just for the purpose of establishing a default transition itself. The default transition mainly affects how transitions are applied to video clips, and addressing audio settings is an additional layer of customization that is typically handled afterward or on a case-by-case basis. Therefore, while all other steps are crucial in the process of setting up a default transition, adjusting the audio settings does not play a role in this specific context.