VideoGrade

A color-grading and film-look engine for video frames — pure Core Image, zero dependencies. One filter builder drives both a live AVPlayerItem.videoComposition and an offline exporter, so preview and export match by construction.

import VideoGrade

var grade = VideoGrade()
grade.contrast = 1.1
grade.splitShadow = .blue
grade.splitShadowAmount = 0.4
grade.grain = 0.2

let filter = try GradeFilter(grade: grade)
let output = filter.apply(inputImage, time: currentTime)   // CIImage → CIImage

What it does

VideoGrade is a pure-data description; GradeFilter resolves it to Core Image.

• Tone / color: exposure, brightness, contrast, saturation, vibrance, temperature, tint, highlights, shadows, levels (black/white/gamma), tone curves (master + per-channel), clarity, brilliance, dehaze.
• Color grading: split-tone (shadow/highlight tints), a per-hue B&W mixer, full 12-band HSL, skin-tone protection.
• Film look: fade, grain, glow/bloom, halation, filmic highlight rolloff, light leaks, anamorphic flare, film damage, chromatic aberration, vignette.
• LUTs: .cube files and PNG "HALD"/square LUTs; Adobe Lightroom .xmp develop presets mapped onto the grade.
• Skin smoothing (SkinSmoothFilter) and cut-transition effects (CutRender — dip to black/white, punch-in, whip-pan, zoom-blur, glitch).

The heavy per-pixel work (B&W mixer, 12-band HSL, split-tone, skin tone, curves, brilliance, dehaze) is baked once into a single 32³ CIColorCube (ColorGradeCube); spatial effects (blur, unsharp, bloom, gradients) are Core Image filter stages. Animated effects (grain, light leaks, film damage) read a time: parameter so they move frame to frame.

Notes

• Parity is the consumer's job: build the filter once and use the same instance for preview and export. A footage effect that looks different in the two is a bug in the host's stage ordering, not here.
• Colors are GradeColor (plain sRGB components), serialized as {red, green, blue, alpha} — the same shape as CaptionKit's StyleColor, so grades embedded in existing documents keep decoding after this split.
• Several algorithms are re-authored from the author-owned FilterSpark shaders as Core Image (no Metal/metallib). brilliance/dehaze are pixel-exact ports; the 12-band HSL uses standard wrapped hue.

Requirements

macOS 26 / iOS 26, Swift 6.2. No external dependencies.

Tests

swift test

License

MIT — see LICENSE.

Bundled or downloaded models keep their own licences; see the notes above where a model is named.