YPbPr

YPbPr or Y'PbPr, also written as , is a color space used in video electronics, in particular in reference to component video cables. Like YCbCr, it is based on gamma corrected RGB primaries; the two are numerically equivalent but YPBPR is designed for use in analog systems while YCBCR is intended for digital video. The EOTF (gamma correction) may be different from common sRGB EOTF and BT.1886 EOTF. Sync is carried on the Y channel and is a bi-level sync signal, but in HD formats a tri-level sync is used and is typically carried on all channels. YPBPR is commonly referred to as component video by manufacturers; however, there are many types of component video, most of which are some form of RGB. Some video cards come with video-in video-out (VIVO) ports for connecting to component video devices. YPBPR is converted from the RGB video signal, which is split into three components: Y, PB, and PR. Y carries luma (brightness or luminance) and synchronization (sync) information. Luma is defined as in SMPTE 274M (1920x1080 resolution) and SMPTE ST 296 (1280x720). It uses BT.709-2 matrix coefficients and digital YCBCR. 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 blue and luma (B − Y). PR carries the difference between red and luma (R − Y). There are other standards of YPBPR components derivation available: 1920x1035 uses SMPTE 240M (240M defined EOTF and uses SMPTE 170M primaries and white point) and 525 lines 60/1.001 Hz (SMPTE 273M) and 625 lines 50 Hz (ITU-R BT.1358) BT.601 matrix is used. To send a green signal as a fourth component is redundant, as it can be derived using the blue, red and luma information. When color signals were first added to the NTSC-encoded black and white video standard, the hue was represented by a phase shift of a color reference sub-carrier.