YPbPr

signal carried by component video cable in consumer electronics. The green cable carries Y, the blue cable carries P B and the red cable carries P R . YPbPr or Y'PbPr, also written as , is a color space used in video electronics, in particular in reference to component video cables. Like YC B C R , it is based on gamma corrected RGB primaries; the two are numerically equivalent but YP B P R is designed for use in analog systems while YC B C R is intended for digital video. The prime symbol indicates presence of gamma correction. YP B P R 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.

signal carried by component video cable in consumer electronics. The green cable carries Y, the blue cable carries P B and the red cable carries P R .]] YPbPr or Y'PbPr, also written as , is a color space used in video electronics, in particular in reference to component video cables. Like YC B C R , it is based on gamma corrected RGB primaries; the two are numerically equivalent but YP B P R is designed for use in analog systems while YC B C R is intended for digital video. The prime symbol indicates presence of gamma correction. YP B P R 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.

Technical details

The definition of Y'PbPr is coupled to its cognate color television standard. The conversion is conceptually very similar, except with the final steps of phase conversion and signal merging omitted. Y'PbPr can be derived from a gamma corrected R'G'B' signal with a typical range of 0-700 mV. The first step is converting to Y' , R'-Y' and B'-Y' using the correct conversion factors: Y' carries luma (brightness or luminance) and synchronization (sync) information. Luma is defined as: Y' = 0.212 R' + 0.701 G' + 0.087 B' for Hi-Vision; Y' = 0.2126 R' + 0.7152 G' + 0.0722 B' for HDTV; Y' = 0.299 R' + 0.587 G' + 0.114 B' for SDTV; R'-Y' and B'-Y' , like their names suggest, are simply obtained by subtracting the calculated luma from the red and blue values. These R'-Y' and B'-Y' values are then scaled to obtain normalized P_b' and P_r' values in the range of +/- 350 or 0-700 mV: P_b' = (B'-Y')/1.826 and P_r' = (R'-Y')/1.576 for Hi-Vision; P_b' = [0.5/(1-0.0722)](B'-Y') and P_r' = [0.5/(1-0.2126)](R'-Y') for HDTV; P_b' = 0.564(B'-Y') and P_r' = 0.713(R'-Y') for SDTV. Alternatively all three output values [Y' P_b' P_r']^\intercal can be represented as the result of multiplying [R' G' B']^\intercal with a 3×3 conversion matrix. These formula are based on SMPTE 240M (240M defined EOTF and uses SMPTE 170M primaries and white point) for Hi-Vision; BT.601 matrix for 525 lines (SMPTE 273M) and 625 lines (ITU-R BT.1358) for SDTV; and SMPTE 274M and SMPTE 296M for HDTV. Different standards often have different matrices. The following table lists example YP B P R values for black, 50% gray and full intensity colors, as defined in ITU-R Recommendation BT.1729: To send a green signal as a fourth component is redundant, as it can be derived using the blue, red and luma information. 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.

References

External links

Color FAQ, Charles Poynton

Text derived from https://en.wikipedia.org/w/index.php?oldid=1377589999 under CC BY-SA 4.0; modifications have been made.