The compositing of videos is considered one of the most important steps on the post-production process. The compositing process combines several videos that may be recorded at different times or locations into a final one. Computer generated footages and visual effects are combined with real footages using video compositing techniques. High reality shots of many movies were introduced to the audience who cannot discover that those shots are not real. Many techniques are used for achieving high realistic results of video compositing. In this paper, a survey of video compositing techniques, a comparison among compositing techniques, and many examples for video compositing using existing techniques are presented.