There are a few ways to preview a movie:
• Space key. When a movie is selected in the thumbnails view, press the space key to preview the movie inline. This is a quick way to peek at the movie if you don't need to see all the details. It's also convenient if you want a small image even for HD videos.
• ⌘Y. Preview in Quick Look. When a movie is selected, press this key combination to open a new window. You can also play the movie in fullscreen from here.
• Open for Editing. Choose "Open for Editing" from the File menu or double-click a selected movie to open it in a new editing pane. You can press the play button to play a movie, or drag in the timeline at the bottom of the window to select a smaller portion. When you press the play button and a selection is set, Clipstart will only play that selection.
When organizing your movies with tags, use the inline preview or Quick Look to watch a few seconds of the movie, then tag appropriately and move on to the next one.