CCIR 601
Encyclopedia
ITU-R
Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601 (or its former name, CCIR 601,) is a standard published in 1982 by International Telecommunication Union - Radiocommunications sector
(formerly CCIR) for encoding interlaced analog video
signals in digital video
form. It includes methods of encoding 525-line 60 Hz
and 625-line 50 Hz signals, both with 720 luminance samples and 360 chrominance
samples per line. The color
encoding system is known as YCbCr 4:2:2
. For a pair of pixels, the data are stored in the order Y1:Cb:Y2:Cr, with the chrominance samples co-sited with the first luminance sample.
The Rec. 601 signal can be regarded as if it is a digitally encoded analog component video
signal, and thus includes data for the horizontal and vertical sync and blanking intervals. Regardless of the frame rate, the luminance sampling frequency is 13.5 MHz. The luminance sample is at least 8 bits, and the chrominance samples are at least 4 bits each.
The first version of Rec. 601 defined only a parallel interface, but later versions introduced the bit-serial family of serial digital video interfaces that are now commonly used. The 8 bit serial protocol (216 Mbit/s) was once used in D1
digital video tape recording. Modern standards use an encoding table to expand the data to 9 or 10 bits for improved behavior over long transmission lines. The 9 bit serial version has a data rate of 243 Mbit/s. By far, the most common version of the interface is the 10-bit serial digital interface
(which was later standardized as SMPTE 259M
), which is now a ubiquitous interconnect standard for professional video equipment which operates on standard-definition digital video. This format, originally used in D5 digital tape recording, has a data rate of 270 Mbit/s.
There is an 8 bit version in which only data from the active video periods are transmitted, with a bit rate of only 165.9 Mbit/s.
In each 8 bit luminance sample, the value 16 is used for black and 235 for white, to allow for overshoot and undershoot. The values 0 and 255 are used for sync encoding. The Cb and Cr samples use the value 128 to encode a zero value, as used when encoding a white, grey or black area.
The Rec. 601 video raster format has been re-used in a number of later standards, including MPEG.
ITU-R
The ITU Radiocommunication Sector is one of the three sectors of the International Telecommunication Union and is responsible for radio communication....
Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601 (or its former name, CCIR 601,) is a standard published in 1982 by International Telecommunication Union - Radiocommunications sector
ITU-R
The ITU Radiocommunication Sector is one of the three sectors of the International Telecommunication Union and is responsible for radio communication....
(formerly CCIR) for encoding interlaced analog video
Analog video
Analog video is a video signal transferred by an analog signal. An analog color video signal contains luminance, brightness and chrominance of an analog television image...
signals in 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 :...
form. It includes methods of encoding 525-line 60 Hz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
and 625-line 50 Hz signals, both with 720 luminance samples and 360 chrominance
Chrominance
Chrominance is the signal used in video systems to convey the color information of the picture, separately from the accompanying luma signal . Chrominance is usually represented as two color-difference components: U = B' − Y' and V = R' − Y'...
samples per line. The color
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
encoding system is known as YCbCr 4:2:2
Chroma subsampling
Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance....
. For a pair of pixels, the data are stored in the order Y1:Cb:Y2:Cr, with the chrominance samples co-sited with the first luminance sample.
The Rec. 601 signal can be regarded as if it is a digitally encoded analog 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...
signal, and thus includes data for the horizontal and vertical sync and blanking intervals. Regardless of the frame rate, the luminance sampling frequency is 13.5 MHz. The luminance sample is at least 8 bits, and the chrominance samples are at least 4 bits each.
The first version of Rec. 601 defined only a parallel interface, but later versions introduced the bit-serial family of serial digital video interfaces that are now commonly used. The 8 bit serial protocol (216 Mbit/s) was once used in D1
D1 (Sony)
D-1 is an SMPTE digital recording video standard, introduced in 1986 through efforts by SMPTE engineering committees. It started as a Sony and Bosch - BTS product and was the first major professional digital video format.- Format :...
digital video tape recording. Modern standards use an encoding table to expand the data to 9 or 10 bits for improved behavior over long transmission lines. The 9 bit serial version has a data rate of 243 Mbit/s. By far, the most common version of the interface is the 10-bit serial digital interface
Serial Digital Interface
Serial digital interface is a family of video interfaces standardized by SMPTE. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video...
(which was later standardized as SMPTE 259M
SMPTE 259M
SMPTE 259M is a standard published by SMPTE which "... describes a 10-bit serial digital interface operating at 143/270/360 Mb/s." The goal of SMPTE 259M is to define a Serial Digital Interface , called SDI or SD-SDI....
), which is now a ubiquitous interconnect standard for professional video equipment which operates on standard-definition digital video. This format, originally used in D5 digital tape recording, has a data rate of 270 Mbit/s.
There is an 8 bit version in which only data from the active video periods are transmitted, with a bit rate of only 165.9 Mbit/s.
In each 8 bit luminance sample, the value 16 is used for black and 235 for white, to allow for overshoot and undershoot. The values 0 and 255 are used for sync encoding. The Cb and Cr samples use the value 128 to encode a zero value, as used when encoding a white, grey or black area.
The Rec. 601 video raster format has been re-used in a number of later standards, including MPEG.
See also
- YCbCrYCbCrYCbCr 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...
- Chroma subsamplingChroma subsamplingChroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance....
- D1 (Sony)D1 (Sony)D-1 is an SMPTE digital recording video standard, introduced in 1986 through efforts by SMPTE engineering committees. It started as a Sony and Bosch - BTS product and was the first major professional digital video format.- Format :...
- Rec. 709Rec. 709ITU-R Recommendation BT.709, more commonly known by the abbreviations Rec. 709 or BT.709, standardizes the format of high-definition television, having 16:9 aspect ratio. The first edition of the standard was approved in 1990....
, the equivalent standard for high-definition televisionHigh-definition televisionHigh-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD... - ITU656
- Pixel aspect ratioPixel aspect ratioPixel aspect ratio is a mathematical ratio that describes how the width of a pixel in a digital image compares to the height of that pixel....