To study the viewer motion with head-mounted displays (HMDs), we setup an experimental environment with Oculus DK2. We developed a software to play 16 videos automatically to viewers. After each view of a video clip, the subject is required to provide a subjective score in the range of 1 to 5. This score is used to detect whether the video content is interesting to the viewer or not. On the other hand, it helps the subject to concentrate on the whole video clip. When a subject is watching a video, his or her motion is recorded and logged. The motion includes 3 degrees of freedom, pitch, yaw, and roll (i.e., X, Y, and Z angles). When wearing a HMD, the viewer's initial position defines the zero degree for pitch, yaw, and roll. Each dimension is denoted by an angle ( -180 degree to 180 degree).