Pronunciation: [ˌə͡ʊvəskˈan] (IPA) 
The word "overscan" is spelled as /ˈoʊvərskæn/. The first syllable "over" is pronounced as /ˈoʊvər/ with the "o" sounding like "oh" and the "er" sounding like "ur" in "nurse". The second syllable "scan" is pronounced as /skæn/ with "s" sounds like "ss" and "a" sounding like "æ" in "cat". Altogether, "overscan" refers to the image or picture that extends beyond the visible area of a screen or display.
Overscan refers to the process of displaying a larger image on a screen by intentionally cropping a small portion of the picture. This technique is commonly used in the field of television and video to eliminate unwanted artifacts or ensure that the entire picture is visible on the screen, especially in older CRT (cathode ray tube) displays.
With overscan, a small area at the edges of the picture is intentionally not shown on the screen, allowing for better alignment or eliminating any noise or distortion caused by the broadcasting or displaying process. This invariably means that a portion of the image is cut off, resulting in a loss of content beyond the visible boundaries of the display. The amount of overscan can vary, depending on the device and settings, but typically ranges from 1% to 5% of the total image area.
Overscan was a crucial adjustment in analog broadcasting, as it helped to compensate for inconsistencies or misalignments across different television sets. However, with the shift towards digital broadcasting and modern display technologies such as LCD and LED screens, overscan is less common and often unnecessary. In fact, many modern devices, such as computers and high-definition televisions, allow users to adjust or disable overscan to ensure a complete view of the content without any cropping.
The term "overscan" originates from the field of television and was coined in the mid-20th century. It combines the prefix "over-" (meaning "excessive" or "beyond") with the word "scan", which refers to the process of moving an electron beam across a display to create an image.
In early television technology, cathode-ray tube (CRT) displays were commonly used, and these displays had a slight curvature at the edges. This curvature caused a small portion of the image to be hidden from view, as the electron beam didn't reach the extreme edges of the screen.
To ensure that no important content was lost, an area beyond the visible edges of the screen was intentionally included in the transmitted signal. This area, referred to as "overscan", contained additional image data that extended beyond what was visible on the actual display.
