In recent years, since broadband communication networks have become widely available, it is possible for ordinary viewers to access video content easily at any time or place with the use of services that deliver video content in a wide diversity of genres. Content delivery services that use user-generated video content have also become popular . As technology supports the creation of video content, video editing systems , computer graphics (CG) software , and the like are being put to practical use. However, technical expertise is needed to use these tools. Furthermore, these tools expect the content creators to take care of key directorial and production roles, such as deciding how the video should be shot, what sort of composition to use, and how to present this content to the viewers. Specialized skills and experiences are needed for these tasks. For ordinary people with no special skills or experiences, the creation of video content can be difficult.