VideoColourCoefficients

Remarks

A record rather than a branch in a loop, because the same six numbers are wanted in two places that cannot share code: VideoColourConversion uses them on the CPU, and a material that samples the three planes uses them in a shader constant block. Deriving them twice is how the two paths end up disagreeing by a hair and only on limited-range BT.601.

Chroma is taken as sample − 128 in every case, so the offset that varies is luma's alone. The scales already carry the 255/219 and 255/224 that limited range needs.

Fields and properties (6)

• public float LumaOffset

  Subtracted from luma before anything else — 16 for limited range, 0 for full.

• public float LumaScale

  What the offset luma is multiplied by.

• public float RedV

  V's contribution to red.

• public float GreenU

  U's contribution to green. Negative.

• public float GreenV

  V's contribution to green. Negative.

• public float BlueU

  U's contribution to blue.

Methods (2)

• public VideoColourCoefficients(float LumaOffset, float LumaScale, float RedV, float GreenU, float GreenV, float BlueU)

  The six numbers that take YUV to RGB, for whoever is doing the arithmetic.

• public static VideoColourCoefficients For(VideoColourMatrix matrix, VideoColourRange range)

  Works out the coefficients for a matrix and a range.

Used by (5)

• VideoColourConversionVixen.Video
• VideoConstantsVixen.Video.Rendering
• VideoConstantsTestsVixen.Video.Rendering.Tests
• VideoTextureVixen.Video
• VideoTextureTestsVixen.Video.Tests