Video Asylum

Posted by ajaynejr on October 04, 2006 at 15:40:44

In Reply to: why we have overscan and 525: the real reason posted by Joe Murphy Jr on August 3, 2006 at 21:13:06:

In the early days of TV the picture (raster) size varied noticeably depending on power line voltage and also as the set aged. When the picture shrank to be smaller than the screen, this was objectionable to many TV set owners and the workaround that manufacturers used was overscan.

Non-subject matter such as microphone booms should not have been included in any part of the video frame even though the producer expected the picture edges to be seen on so few TV sets due to overscan.

After discounting the 5% strips around all four edges, the safe action area comes out to about 81% of the total video frame. After discounting the 10% strips around the edges, the safe title area comes out to about 64% of the total video frame.

• http://members.aol.com/ajaynejr/video.htm   (Open in New Window)