There are two video preview modes: Clip mode and Movie mode.
In Clip mode, only the clip that is selected on the timeline is played, and playback stops once the end of the clip is reached.
In Movie mode, the entire video production is played from the current timeline slider position to the end of the production (where the media clips end).
You can select one of the following five preview resolutions: Low Preview Resolution, Normal Preview Resolution, High Preview Resolution, HD Preview Resolution, and Full HD Preview Resolution. If your computer has low or limited resources, it is recommended that you select Low Preview Resolution or Normal Preview Resolution for a smoother preview playback. Selecting a lower resolution does not affect the quality of the outputted video.
Click on the button to select the preview resolution from the Preview Quality option.
If your computer is running on a 32 bit operating system, only these three resolution options are available to you: Low Preview Resolution, Normal Preview Resolution, and High Preview Resolution. The HD Preview Resolution and Full HD Preview Resolution options are only available on computers running on a 64 bit operating system.