YPbPr
Encyclopedia
is a color space
used in video
electronics, in particular in reference to component video
cables. is the analog
version of the YCBCR
color space; the two are numerically equivalent, but YPBPR is designed for use in analog systems
whereas YCBCR is intended for digital video
.
cables are also commonly referred to as Yipper cables. is commonly called "component video", but this is imprecise, as there are many other types of component video (mostly RGB with sync either on green or one or two separate signals).
Some video card
s come with Video In Video Out (VIVO)
ports for connecting to component video devices.
video signal, which is split into three components, Y, PB, and PR.
Sending a green
signal would be redundant, as it can be derived using the blue, red and luma information.
When color signals were first added to NTSC encoded black and white video standard, the hue was represented by a phase shift of a color reference sub-carrier. P for Phase information or Phase Shift has carried through to represent color information even in the case where there is no longer a phase shift used to represent hue. Thus the Y Pb Pr nomenclature derives from engineering metrics developed for the NTSC color standard.
The same cables can be used for and composite video
. This means that the yellow RCA connector
cable commonly packaged with most audio/visual equipment can be used in place of the connectors, provided the end user is careful to keep track of the device functions (i.e. connect any one of the individual functions to the corresponding function on the other end using any cable color).
and composite video
mix the signals together by means of electronic multiplexing
, however, more often than not the signal is degraded at the display end as the display is not able to separate the signals completely. It is possible for their multiplexed counterparts to interfere with each other (see dot crawl
).
Signals that use , like other forms of component video, offer enough separation of the signals that no multiplexing is needed, so the quality of the extracted image is generally nearly identical to the signal before encoding.
Though not necessarily an advantage to , component video which uses is the only one out of the three common analog cable standards (the other two being composite and S-Video) that is able to transfer non-interlaced video and at the same time able to transfer resolutions higher than 480i/p (NTSC) or 576i/p (PAL).
Color space
A 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...
used in video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
electronics, in particular in reference to component video
Component video
Component 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...
cables. is the analog
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
version of the YCBCR
YCbCr
YCbCr or Y′CbCr, sometimes written or , is a family of color spaces used as a part of the color image pipeline in video and digital photography systems. Y′ is the luma component and CB and CR are the blue-difference and red-difference chroma components...
color space; the two are numerically equivalent, but YPBPR is designed for use in analog systems
Analogue electronics
Analogue electronics are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two different levels. The term "analogue" describes the proportional relationship between a signal and a voltage or current that represents the signal...
whereas YCBCR is intended for digital video
Digital video
Digital video is a type of digital recording system that works by using a digital rather than an analog video signal.The terms camera, video camera, and camcorder are used interchangeably in this article.- History :...
.
cables are also commonly referred to as Yipper cables. is commonly called "component video", but this is imprecise, as there are many other types of component video (mostly RGB with sync either on green or one or two separate signals).
Some video card
Video card
A video card, Graphics Card, or Graphics adapter is an expansion card which generates output images to a display. Most video cards offer various functions such as accelerated rendering of 3D scenes and 2D graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors...
s come with Video In Video Out (VIVO)
Video In Video Out
Video In Video Out, usually seen as the acronym VIVO , is a graphics port which enables some video cards to have bidirectional analog video transfer through a mini-DIN connector, usually of the 9-pin variety, and a specialised splitter cable .VIVO is found on high-end ATI and NVIDIA...
ports for connecting to component video devices.
Technical details
is converted from the RGBRGB color model
The 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...
video signal, which is split into three components, Y, PB, and PR.
- Y carries lumaLuma (video)In video, luma, sometimes called luminance, represents the brightness in an image . Luma is typically paired with chrominance. Luma represents the achromatic image without any color, while the chroma components represent the color information...
(brightness or luminance) and synchronization (sync) information. Y = 0.2126 R + 0.7152 G + 0.0722 B Before the advent of color television, the Y axis on an oscilloscope display of a video waveform represented the intensity of the scan line. With color, Y still represents intensity but it is a composite of the component colors. - PB carries the difference between blueBlueBlue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
and luma (B − Y). - PR carries the difference between redRedRed is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
and luma (R − Y).
Sending a green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
signal would be redundant, as it can be derived using the blue, red and luma information.
When color signals were first added to NTSC encoded black and white video standard, the hue was represented by a phase shift of a color reference sub-carrier. P for Phase information or Phase Shift has carried through to represent color information even in the case where there is no longer a phase shift used to represent hue. Thus the Y Pb Pr nomenclature derives from engineering metrics developed for the NTSC color standard.
The same cables can be used for and composite video
Composite video
Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
. This means that the yellow RCA connector
RCA connector
An RCA connector, sometimes called a phono connector or cinch connector, is a type of electrical connector commonly used to carry audio and video signals...
cable commonly packaged with most audio/visual equipment can be used in place of the connectors, provided the end user is careful to keep track of the device functions (i.e. connect any one of the individual functions to the corresponding function on the other end using any cable color).
Advantages
is a color space encoding scheme that was developed to save on cable bandwidth requirements while separating the signal enough to provide a quality image. S-VideoS-Video
Separate Video, more commonly known as S-Video and Y/C, is often referred to by JVC as both an S-VHS connector and as Super Video. It is an analog video transmission scheme, in which video information is encoded on two channels: luma and chroma...
and composite video
Composite video
Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
mix the signals together by means of electronic multiplexing
Multiplexing
The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...
, however, more often than not the signal is degraded at the display end as the display is not able to separate the signals completely. It is possible for their multiplexed counterparts to interfere with each other (see dot crawl
Dot crawl
Dot crawl is the popular name for a visual defect of color analog video standards when signals are transmitted as composite video, as in terrestrial broadcast television. It consists of animated checkerboard patterns which appear along vertical color transitions...
).
Signals that use , like other forms of component video, offer enough separation of the signals that no multiplexing is needed, so the quality of the extracted image is generally nearly identical to the signal before encoding.
Though not necessarily an advantage to , component video which uses is the only one out of the three common analog cable standards (the other two being composite and S-Video) that is able to transfer non-interlaced video and at the same time able to transfer resolutions higher than 480i/p (NTSC) or 576i/p (PAL).
External links
- Color FAQ, Charles Poynton
- Color formats for image and video processing - Color conversion between RGB, YUV, YCbCr and YPbPr.