OVERSCAN

This term describes the active image area in a video picture that is outside the edges of the display device. Overscan first came about because it was felt that consumers wanted the entire image area of their screen filled with picture information. To accomplish that reliably it was necessary to push the outside edge of the active picture area of the video signal out beyond the edge of the display area. In the early days of television set construction, where parts tolerances and AC line voltage fluctuations would influence how much of the image went out beyond the edge of the picture area, it was decided to loose 5% of the image on each edge. This became the average or targeted Overscan. In some cases it could go as high as 10%. Program producers had to be aware that image information at these outside edges might not be seen by the majority of the viewers so they established a reference for themselves. The area inside a 5% line around the edges of the picture was called the "Safe Action" area. The area inside 10% lines was called "Safe Title". The Overscan Test Pattern can be found at VE T15 C7 or VE T17 C8.