Direct Manipulation Video Navigation (DMVN) systems allow a user to directly drag an object of interest along its motion trajectory and have been shown effective for space-centric video browsing tasks. This paper designs touch-based interface techniques to support DMVN on touchscreen devices. While touch screens can suit DMVN systems naturally and enhance the directness during video navigation, the fat finger problems, such as precise selection and occlusion handling, must be properly addressed. In this paper, we discuss the effect of the fat finger problems on DMVN and develop three touch-based object dragging techniques for DMVN on touch screens, namely Offset Drag, Window Drag, and Drag Anywhere. We conduct user studies to evaluate our techniques as well as two baseline solutions on a smartphone and a desktop touch screen. Our studies show that two of our techniques can support DMVN on touch screen devices well and perform better than the baseline solutions.