Video scaler
Encyclopedia
A video scaler is a device for converting video
signals from one size or resolution
to another: usually "upscaling" or "upconverting" a video signal from a low resolution (e.g. standard definition) to one of higher resolution (e.g. high definition television).
Video scaler devices can be found embedded in:
Video scalers can also be a completely separate box, often providing simple video switching capabilities. These units are commonly found as part of home theatre
or projected presentation systems. Home theatre uses might include converting a standard definition DVD or video game signal into high-definition for display on an LED
, LCD or plasma television while obtaining the best image quality
possible. Scalers can also be found in schools, lecture theatres and modern churches, where numerous video sources (e.g. DVD video, live camera feeds, DVI
/VGA
output from a computer) need to be switched between, while the highest possible resolution is maintained.
Video scalers are primarily a digital
device, however they can be combined with an analog-to-digital converter
(ADC, or digitizer) and a digital-to-analog converter
(DAC) to support analog inputs and outputs. One upscaling process that has gotten a lot of attention is the IMAX DMR.
The "native resolution
" of a display is how many physical pixels make up each row and column of the visible area on the display's output surface. There are many different video signals in use which are not the same resolution (neither are all of the displays), thus some form of resolution adaptation (video scaling) is required to properly frame a video signal to a display device. For example, within the United States
, there are NTSC
, ATSC
, and VESA
video standards each with several different resolution video formats.
devices or algorithms to create a video processor that improves the apparent definition
of video signals. These other devices may include the ability for:
These can either be in chip form, or as a stand alone unit to be placed between a source device (like a DVD player or set-top-box) and a display with less-capable processing. The most widely recognized video processor companies in the market as of June 2007 are:
All of these companies' chips are in devices ranging from DVD upconverting players (for Standard Definition) to HD DVD
/Blu-Ray Disc players and set-top boxes, to displays like plasmas, DLP (both front and rear projection), LCD
(both flat-panels
and projectors
), and LCOS/”SXRD
”. Their chips are also becoming more available in stand alone devices (see "External links" below for links to a few of these).
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
signals from one size or resolution
Display resolution
The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...
to another: usually "upscaling" or "upconverting" a video signal from a low resolution (e.g. standard definition) to one of higher resolution (e.g. high definition television).
Video scaler devices can be found embedded in:
- Computer monitors
- Scan conversionScan conversionScan conversion or scan rate converting is a video processing technique for changing the vertical / horizontal scan frequency of video signal for different purposes and applications...
devices - Televisions
- Video editingVideo editingThe term video editing can refer to:* Linear video editing, using video tape* Non-linear editing system , using computers with video editing software* Offline editing* Online editing...
and broadcastingBroadcastingBroadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
equipment - Other audio/visual devices
Video scalers can also be a completely separate box, often providing simple video switching capabilities. These units are commonly found as part of home theatre
Home cinema
Home cinema, also commonly called home theater, are home entertainment set-ups that seek to reproduce a movie theater experience and mood with the help of video and audio equipment in a private home....
or projected presentation systems. Home theatre uses might include converting a standard definition DVD or video game signal into high-definition for display on an LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....
, LCD or plasma television while obtaining the best image quality
Image Quality
Image quality is a characteristic of an image that measures the perceived image degradation . Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem.-In photographic imaging:In digital or film-based photography, an...
possible. Scalers can also be found in schools, lecture theatres and modern churches, where numerous video sources (e.g. DVD video, live camera feeds, DVI
Digital Visual Interface
The Digital Visual Interface is a video interface standard covering the transmission of video between a source device and a display device. The DVI standard has achieved widespread acceptance in the PC industry, both in desktop PCs and monitors...
/VGA
Video Graphics Array
Video Graphics Array refers specifically to the display hardware first introduced with the IBM PS/2 line of computers in 1987, but through its widespread adoption has also come to mean either an analog computer display standard, the 15-pin D-subminiature VGA connector or the 640×480 resolution...
output from a computer) need to be switched between, while the highest possible resolution is maintained.
Video scalers are primarily a digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
device, however they can be combined with an analog-to-digital converter
Analog-to-digital converter
An analog-to-digital converter is a device that converts a continuous quantity to a discrete time digital representation. An ADC may also provide an isolated measurement...
(ADC, or digitizer) and a digital-to-analog converter
Digital-to-analog converter
In electronics, a digital-to-analog converter is a device that converts a digital code to an analog signal . An analog-to-digital converter performs the reverse operation...
(DAC) to support analog inputs and outputs. One upscaling process that has gotten a lot of attention is the IMAX DMR.
Scaling a signal to match the display
Native resolution
The native resolution of a LCD, LCoS or other flat panel display refers to its single fixed resolution. As an LCD display consists of a fixed raster, it cannot change resolution to match the signal being displayed as a CRT monitor can, meaning that optimal display quality can be reached only when...
" of a display is how many physical pixels make up each row and column of the visible area on the display's output surface. There are many different video signals in use which are not the same resolution (neither are all of the displays), thus some form of resolution adaptation (video scaling) is required to properly frame a video signal to a display device. For example, within the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, there are NTSC
NTSC
NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
, ATSC
ATSC
ATSC standards are a set of standards developed by the Advanced Television Systems Committee for digital television transmission over terrestrial, cable, and satellite networks....
, and VESA
VESA
VESA is an international standards body for computer graphics founded in 1989 by NEC Home Electronics and eight other video display adapter manufacturers.VESA's initial goal was to produce a standard for 800×600 SVGA resolution video displays...
video standards each with several different resolution video formats.
Image artifacts/errors related to video scaling
- Banding or posterizationPosterizationPosterization of an image entails conversion of a continuous gradation of tone to several regions of fewer tones, with abrupt changes from one tone to another. This was originally done with photographic processes to create posters...
- Scaler ringing
- Double scaling – When a source device is used which upscales to a resolution not native to a television's display, the TV can scale the image a second time which unnecessarily reduces the final output quality.
Video processor
Video scalers are often combined with other video processingVideo processing
In electrical engineering and computer science, video processing is a particular case of signal processing, which often employs video filters and where the input and output signals are video files or video streams. Video processing techniques are used in television sets, VCRs, DVDs, video codecs,...
devices or algorithms to create a video processor that improves the apparent definition
Improved-definition television
Improved-definition television or enhanced-quality television transmitters and receivers exceed the performance requirements of the NTSC standard, while remaining within the general parameters of NTSC emissions standards....
of video signals. These other devices may include the ability for:
- deinterlacingDeinterlacingDeinterlacing is the process of converting interlaced video, such as common analog television signals or 1080i format HDTV signals, into a non-interlaced form....
- aspect ratioAspect ratioThe aspect ratio of a shape is the ratio of its longer dimension to its shorter dimension. It may be applied to two characteristic dimensions of a three-dimensional shape, such as the ratio of the longest and shortest axis, or for symmetrical objects that are described by just two measurements,...
control - digital zoomDigital zoomDigital zoom is a method of decreasing the apparent angle of view of a digital photographic or video image. Digital zoom is accomplished by cropping an image down to a centered area with the same aspect ratio as the original, and usually also interpolating the result back up to the pixel...
and panPanning (camera)In photography, panning refers to the horizontal movement or rotation of a still or video camera, or the scanning of a subject horizontally on video or a display device... - brightnessBrightnessBrightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target...
/contrastContrast (vision)Contrast is the difference in visual properties that makes an object distinguishable from other objects and the background. In visual perception of the real world, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view...
/hueHueHue is one of the main properties of a color, defined technically , as "the degree to which a stimulus can be describedas similar to or different from stimuli that are described as red, green, blue, and yellow,"...
/saturationSaturation (color theory)In colorimetry and color theory, colorfulness, chroma, and saturation are related but distinct concepts referring to the perceived intensity of a specific color. Colorfulness is the degree of difference between a color and gray. Chroma is the colorfulness relative to the brightness of another color...
/sharpness/gammaGamma correctionGamma correction, gamma nonlinearity, gamma encoding, or often simply gamma, is the name of a nonlinear operation used to code and decode luminance or tristimulus values in video or still image systems...
adjustments - frame rateFrame rateFrame rate is the frequency at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems...
conversion and inverse-telecine - color point conversion (601 to 709 or 709 to 601)
- color spaceColor spaceA color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components...
conversion (ComponentComponent videoComponent video is a video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video information that is transmitted or stored as three separate signals...
to RGBRGB color modelThe RGB color model is an additive color model in which red, green, and blue light is added together in various ways to reproduce a broad array of colors...
or RGB to Component) - mosquito noiseCompression artifactA compression artifact is a noticeable distortion of media caused by the application of lossy data compression....
reduction - block noiseCompression artifactA compression artifact is a noticeable distortion of media caused by the application of lossy data compression....
reduction - detail enhancement
- edge enhancement
- motion compensationMotion compensationMotion compensation is an algorithmic technique employed in the encoding of video data for video compression, for example in the generation of MPEG-2 files. Motion compensation describes a picture in terms of the transformation of a reference picture to the current picture. The reference picture...
- primary and secondary color calibration (including hue/saturation/luminance controls independently for each)
These can either be in chip form, or as a stand alone unit to be placed between a source device (like a DVD player or set-top-box) and a display with less-capable processing. The most widely recognized video processor companies in the market as of June 2007 are:
- Genesis Microchip (with the FLI chipset – was Genesis Microchip, STMicroelectronics completes acquisition of Genesis Microchip on 01/25/08)
- Sigma Designs (with the VXP chipset – was Gennum, Sigma Designs purchased the Image Processing group from Gennum on February 8, 2008)
- Integrated Device Technology (with the HQV chipset and Teranex system products – was Silicon Optix, IDT purchased SO on October 21, 2008)
- Simplay Labs - Silicon Image (with the VRS chipset and DVDO system products - was Anchor Bay Technologies, Silicon Image purchased ABT on Feb 10, 2011)
All of these companies' chips are in devices ranging from DVD upconverting players (for Standard Definition) to HD DVD
HD DVD
HD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...
/Blu-Ray Disc players and set-top boxes, to displays like plasmas, DLP (both front and rear projection), LCD
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
(both flat-panels
Liquid crystal display television
Liquid-crystal display televisions are television sets that use LCD display technology to produce images. LCD televisions are thinner and lighter than cathode ray tube of similar display size, and are available in much larger sizes...
and projectors
LCD projector
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector...
), and LCOS/”SXRD
SXRD
SXRD is Sony's proprietary variant of liquid crystal on silicon, a technology used mainly in projection televisions and video projectors. In the front and rear-projection television market, it competes directly with JVC's D-ILA and Texas Instruments' DLP...
”. Their chips are also becoming more available in stand alone devices (see "External links" below for links to a few of these).
See also
- Display resolutionDisplay resolutionThe display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...
- DeinterlacingDeinterlacingDeinterlacing is the process of converting interlaced video, such as common analog television signals or 1080i format HDTV signals, into a non-interlaced form....
- DitherDitherDither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images...
- Video display standards
- Stretch-o-VisionStretch-o-VisionStretch-o-Vision is a neologism used to describe the practice of upconverting video from a standard aspect ratio to a widescreen aspect ratio. HDTV programming is broadcast in the 16:9 aspect ratio, a widescreen image. However, most SDTV programming is usually broadcast in the 4:3 aspect ratio....
- DVD recorderDVD recorderA DVD recorder , is an optical disc recorder that uses Optical disc recording technologies to digitally record analog signal or digital signals onto blank writable DVD media...