An on-screen display is an image superimposed on a screen picture, commonly used by modern television set

Television set

A television set is a device that combines a tuner, display, and speakers for the purpose of viewing television. Television sets became a popular consumer product after the Second World War, using vacuum tubes and cathode ray tube displays...

s, VCRs, and DVD player

DVD player

A DVD player is a device that plays discs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. These devices were invented in 1997 and continue to thrive...

s to display information such as volume, channel, and time.

History

In the past, most adjustments on TV sets were performed by means of analog controls, like potentiometer

Potentiometer

A potentiometer , informally, a pot, is a three-terminal resistor with a sliding contact that forms an adjustable voltage divider. If only two terminals are used , it acts as a variable resistor or rheostat. Potentiometers are commonly used to control electrical devices such as volume controls on...

s and switches. This is still used in modern monochrome portable TVs. After remote control

Remote control

A remote control is a component of an electronics device, most commonly a television set, used for operating the television device wirelessly from a short line-of-sight distance.The remote control is usually contracted to remote...

s were invented, digital adjustments became common. They needed an external display, which was LED

LEd

LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

, LCD, or VFD

Vacuum fluorescent display

A vacuum fluorescent display is a display device used commonly on consumer-electronics equipment such as video cassette recorders, car radios, and microwave ovens. Invented in Japan in 1967, the displays became common on calculators and other consumer electronics devices...

 based. Including this display increased manufacturing costs.

When electronics

Electronics

Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

 became more advanced, it became clear that adding some extra devices for an OSD was cheaper than adding a second display device. TV screens had also become much bigger and could display much more information than a tiny second display. OSDs display graphical information superimposed over the picture, which is done by synchronizing the reading from OSD video memory with the TV signal.

On-screen displays first began to appear in the 1980s on televisions. By the mid-1990s, VCRs with these displays became widely available. This made it possible to reduce the size (and cost) of the VFDs used in VCRs. Akai

Akai

Akai is a consumer electronics brand, founded by Saburo Akai as , a Japanese manufacturer in 1929. It is now headquartered in Singapore as a subsidiary of Grande Holdings, a Hong Kong-based conglomerate, which also owns the formerly Japanese brands Nakamichi and Sansui. The Akai brand is now used...

 have been credited with the introduction of OSD in VCRs in the 1980s, including the introduction of on screen programming. All DVD players also use on-screen displays. Many PAL

PAL

PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...

 television sets use the internal Teletext

Teletext

Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...

 decoder's graphics rendering system to further reduce costs.

More recently (as of about 2005), the decline in CRT

Cathode ray tube

The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 based television sets and rise in LCD/plasma

Plasma display

A plasma display panel is a type of flat panel display common to large TV displays or larger. They are called "plasma" displays because the technology utilizes small cells containing electrically charged ionized gases, or what are in essence chambers more commonly known as fluorescent...

 televisions has seen the use and availability of dedicated OSD devices decline, as it is more cost effective to integrate OSD functions inside the main graphics processor. Modern LCD television monitors will usually incorporate only two or three integrated circuits. Examples of integrated circuits to perform dedicated OSD are MAX7456 and STV5730. Both operate with NTSC or PAL, mixing with an existing signal or self-generating. Both have slightly different capabilities. This can be done by PIC video superimposer too.

Computers

Some computer software

Computer software

Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....

 also uses OSDs, especially support programs for so-called "enhanced keyboard

Computer keyboard

In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

s", which often had additional media keys for actions like skipping through music tracks and volume adjustment. Their use outside this field is still uncommon. On-screen displays are also used in camcorder

Camcorder

A camcorder is an electronic device that combines a video camera and a video recorder into one unit. Equipment manufacturers do not seem to have strict guidelines for the term usage...

s, and can display various information both on the viewfinder and on the TV set the camcorder is connected to.

The complexity of graphics offered by such displays has greatly increased over the years, from simple monochrome

Monochrome

Monochrome describes paintings, drawings, design, or photographs in one color or shades of one color. A monochromatic object or image has colors in shades of limited colors or hues. Images using only shades of grey are called grayscale or black-and-white...

 images to intricate graphical user interface

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

s.

Criticism

Several problems exist with regard to on-screen displays. One of them is diagnostics in case a television's display system is damaged. Without any external screens, it is almost impossible (without opening the television) to determine the source of the error. Television accessories that depend heavily on OSDs, such as VCRs or DVD players, are also very difficult to configure without the use of a television. On older VCRs, for example, it was possible to set up recording timers without turning on the TV; a modern VCR requires the user to turn on his or her TV to do so. Usability is generally also decreased with OSDs, as it is necessary to control a multitude of parameters with a few buttons only, where earlier, real analog controls with mechanical feedback were available.

The drawbacks of using OSDs do not outweigh their main advantage of being more cost-efficient, which has led to their widespread use. Although, in some underground communities the use of an OSD is regarded software bloat

Software bloat

Software bloat is a process whereby successive versions of a computer program include an increasing proportion of unnecessary features that are not used by end users, or generally use more system resources than necessary, while offering little or no benefit to its users.-Causes:Software developers...

and is highly frowned upon.

Hobbyist use of OSD can provide significant benefit in terms of the amount of information that can be shown without resorting to specific displays (e.g.: dot matrix LCD or computer displays), as virtually every home has a TV.