From a05d97a0e929c54fa8a3e1e461a11cfa9b8fd8b2 Mon Sep 17 00:00:00 2001 From: Camille Moine Date: Mon, 19 Oct 2026 20:44:32 +0200 Subject: [PATCH] effects: speed up Match Grain's CPU analysis The sample-box search rescanned every candidate box and the grain statistics blurred the whole image three times per layer, although Match Grain only reads the 80 sample boxes (~6.5k pixels). On a 4K frame that analysis was ~90 % of the effect. - measure the statistics from small crops around each box (3 px halo, the Gaussian's support), deduplicating overlapping boxes so the sums match the previous masked version; - search the candidate box rows in parallel (the sort is a total order, so the chosen boxes are unchanged); - compute the "own" boxes and stats only when Compensate for Existing Noise is on, and clone the frame for Preview composition only in Preview mode; - run Plane::transpose/map_rows on the calling thread for small planes: the rayon dispatch dominated per-box crops (240 blurs of ~15x15). Release, Ryzen Threadripper 1920X, noisy source / flat target, defaults, best of 4 (1080p / 4K): - grain statistics: 151/463 ms -> 1.2/2.8 ms - sample boxes (source): 43/179 ms -> 16/71 ms - end to end: 266/1416 ms -> 99/465 ms (Compensate 50 %: 392/1830 -> 104/482) Tests: the boxed statistics match the masked ones (overlapping and corner boxes, alpha holes), plus the existing Match Grain/Remove Grain suites. --- crates/effects/src/noise.rs | 52 +++++----- crates/effects/src/noise2.rs | 186 ++++++++++++++++++++++++++++++----- crates/effects/src/util.rs | 18 ++++ 3 files changed, 206 insertions(+), 50 deletions(-) diff --git a/crates/effects/src/noise.rs b/crates/effects/src/noise.rs index d39fd6528..9d21e77a7 100644 --- a/crates/effects/src/noise.rs +++ b/crates/effects/src/noise.rs @@ -264,25 +264,30 @@ pub(crate) fn sample_boxes(img: &Image, count: usize, size: usize) -> Vec<(usize } let low = Plane::luma(img); let step = (size / 2).max(1); - let mut cands: Vec<(f32, usize, usize)> = Vec::new(); - for y in (0..=h - size).step_by(step) { - for x in (0..=w - size).step_by(step) { - // Variance of the picture inside the box (the flattest boxes hold the least detail). - let (mut s, mut sq, mut n, mut opaque) = (0.0f32, 0.0f32, 0.0f32, true); - for yy in y..y + size { - for xx in x..x + size { - let v = low.data[yy * w + xx]; - s += v; - sq += v * v; - n += 1.0; - opaque &= img.data[yy * w + xx][3] > 0.5; + // Candidate rows in parallel; the sort below is a total order (variance, y, x), so the + // result does not depend on the collection order. + let rows: Vec = (0..=h - size).step_by(step).collect(); + let mut cands: Vec<(f32, usize, usize)> = rows + .par_iter() + .flat_map_iter(|&y| { + let data = low.data.as_slice(); + let alpha = img.data.as_slice(); + (0..=w - size).step_by(step).filter_map(move |x| { + // Variance of the picture inside the box (the flattest boxes hold the least detail). + let (mut s, mut sq, mut n, mut opaque) = (0.0f32, 0.0f32, 0.0f32, true); + for yy in y..y + size { + for xx in x..x + size { + let v = data[yy * w + xx]; + s += v; + sq += v * v; + n += 1.0; + opaque &= alpha[yy * w + xx][3] > 0.5; + } } - } - if opaque { - cands.push((sq / n - (s / n).powi(2), x, y)); - } - } - } + opaque.then(|| (sq / n - (s / n).powi(2), x, y)) + }) + }) + .collect(); cands.sort_by(|a, b| a.0.total_cmp(&b.0).then(a.2.cmp(&b.2)).then(a.1.cmp(&b.1))); cands.into_iter().take(count).map(|(_, x, y)| (x, y, size)).collect() } @@ -479,16 +484,7 @@ pub(crate) fn sampling_boxes(ctx: &EffectCtx, img: &Image, scale: f64) -> Vec<(u /// The grain level (0.5..2) measured in the sample boxes of `img`. fn grain_level(img: &Image, boxes: &[(usize, usize, usize)]) -> f32 { - let mut m = vec![false; img.data.len()]; - let w = img.width as usize; - for &(x, y, s) in boxes { - for yy in y..y + s { - for xx in x..x + s { - m[yy * w + xx] = true; - } - } - } - let st = crate::noise2::grain_stats_masked(img, Some(&m)); + let st = crate::noise2::grain_stats_boxes(img, boxes); let s = (st.std[0] + st.std[1] + st.std[2]) / 3.0; if boxes.is_empty() { 1.0 } else { (s / 0.02).clamp(0.5, 2.0) } } diff --git a/crates/effects/src/noise2.rs b/crates/effects/src/noise2.rs index 4c22f6d8f..cfdd4764e 100644 --- a/crates/effects/src/noise2.rs +++ b/crates/effects/src/noise2.rs @@ -75,6 +75,101 @@ pub(crate) fn grain_stats_masked(img: &Image, mask: Option<&[bool]>) -> GrainSta GrainStats { std, size: (1.0 / (1.0 - rho as f32)).clamp(0.5, 20.0) * 0.6 } } +/// Grain statistics over sample `boxes` (in image pixels), measured from small crops around each +/// box instead of the whole image. Empty `boxes` measures every opaque pixel, like +/// [`grain_stats_masked`] without a mask. Overlapping boxes are deduplicated, so the sums match +/// the masked version. +pub(crate) fn grain_stats_boxes(img: &Image, boxes: &[(usize, usize, usize)]) -> GrainStats { + if boxes.is_empty() { + return grain_stats_masked(img, None); + } + let (w, h) = (img.width as usize, img.height as usize); + if w < 3 || h < 3 { + return GrainStats::default(); + } + // The Gaussian's three box passes at sigma 1.5 have radius 1 each, so a 3 px halo is enough + // for the high-pass residual of every pixel inside a box. + const HALO: usize = 3; + let mut mask = vec![false; w * h]; + for &(x, y, s) in boxes { + for yy in y..y.saturating_add(s).min(h) { + for xx in x..x.saturating_add(s).min(w) { + mask[yy * w + xx] = true; + } + } + } + let mut counted = vec![false; w * h]; + let mut n = [0.0f64; 3]; + let mut sum = [0.0f64; 3]; + let mut sq = [0.0f64; 3]; + let mut rho_num = 0.0f64; + let mut rho_den = 0.0f64; + let mut crop: Vec<([f32; 3], f32)> = Vec::new(); + let mut planes: Vec = Vec::new(); + for &(bx, by, bs) in boxes { + let x0 = bx.saturating_sub(HALO); + let y0 = by.saturating_sub(HALO); + let x1 = bx.saturating_add(bs).saturating_add(HALO).min(w); + let y1 = by.saturating_add(bs).saturating_add(HALO).min(h); + if x1 <= x0 || y1 <= y0 { + continue; + } + let (cw, ch) = (x1 - x0, y1 - y0); + crop.clear(); + crop.extend((y0..y1).flat_map(|y| (x0..x1).map(move |x| unpremul(img.data[y * w + x])))); + planes.clear(); + for k in 0..3 { + let pl = Plane { w: cw, h: ch, data: crop.iter().map(|s| s.0[k]).collect() }; + planes.push(gauss_plane(&pl, 1.5, 1.5)); + } + for ly in 0..bs { + let y = by + ly; + if y >= h { + break; + } + for lx in 0..bs { + let x = bx + lx; + if x >= w { + break; + } + let g = y * w + x; + if !mask[g] || counted[g] { + continue; + } + counted[g] = true; + let l = (y - y0) * cw + (x - x0); + let (_, a) = crop[l]; + if a <= 0.5 { + continue; + } + for k in 0..3 { + let hp = crop[l].0[k] - planes[k].data[l]; + sum[k] += hp as f64; + sq[k] += (hp as f64) * (hp as f64); + n[k] += 1.0; + } + if x + 1 < w && mask[g + 1] && crop[l + 1].1 > 0.5 { + for k in 0..3 { + let hp = crop[l].0[k] - planes[k].data[l]; + let hn = crop[l + 1].0[k] - planes[k].data[l + 1]; + rho_num += (hp * hn) as f64; + rho_den += (hp * hp) as f64; + } + } + } + } + } + let mut std = [0.0f32; 3]; + for k in 0..3 { + if n[k] > 1.0 { + let mean = sum[k] / n[k]; + std[k] = ((sq[k] / n[k] - mean * mean).max(0.0)).sqrt() as f32; + } + } + let rho = if rho_den > 1e-12 { (rho_num / rho_den).clamp(0.0, 0.95) } else { 0.0 }; + GrainStats { std, size: (1.0 / (1.0 - rho as f32)).clamp(0.5, 20.0) * 0.6 } +} + /// Match Grain's Viewing Mode options. const MATCH_GRAIN_VIEWS: [&str; 5] = ["Preview", "Noise Samples", "Compensation Samples", "Blending Matte", "Final Output"]; @@ -86,34 +181,24 @@ fn match_grain(ctx: &EffectCtx, mut b: Buf) -> Buf { let view = ctx.params.e("viewingMode"); let source = layer_or_self(ctx, &b, "noiseSourceLayer", false, false); let src_boxes = sampling_boxes(ctx, &source, b.scale); - let own_boxes = sampling_boxes(ctx, &b.img, b.scale); let box_col = ctx.params.get("sampling/sampleBoxColor").map(|v| v.as_color()).unwrap_or([1.0, 1.0, 0.0, 1.0]); if view == 1 || view == 2 { // Noise Samples (on the source) / Compensation Samples (on this layer). - let (mut img, boxes) = if view == 1 { (source, src_boxes) } else { (b.img.clone(), own_boxes) }; + let (mut img, boxes) = if view == 1 { (source, src_boxes) } else { (b.img.clone(), sampling_boxes(ctx, &b.img, b.scale)) }; draw_boxes(&mut img, &boxes, box_col); b.img = img; return b; } - let mask_of = |img: &Image, boxes: &[(usize, usize, usize)]| -> Option> { - if boxes.is_empty() { - return None; - } - let w = img.width as usize; - let mut m = vec![false; img.data.len()]; - for &(x, y, s) in boxes { - for yy in y..y + s { - for xx in x..x + s { - m[yy * w + xx] = true; - } - } - } - Some(m) - }; - let src_stats = grain_stats_masked(&source, mask_of(&source, &src_boxes).as_deref()); + let src_stats = grain_stats_boxes(&source, &src_boxes); let comp = (ctx.params.f("compensateForExistingNoise") / 100.0) as f32; - let own = if comp > 0.0 { grain_stats_masked(&b.img, mask_of(&b.img, &own_boxes).as_deref()) } else { GrainStats::default() }; - let orig = b.img.clone(); + // The own-layer boxes only matter for the compensation term; skip them when it is off. + let own = if comp > 0.0 { + let own_boxes = sampling_boxes(ctx, &b.img, b.scale); + grain_stats_boxes(&b.img, &own_boxes) + } else { + GrainStats::default() + }; + let orig = (view == 0).then(|| b.img.clone()); let look = GrainLook::from_params(ctx); let amp: [f32; 3] = [0, 1, 2].map(|k| { let s = src_stats.std[k]; @@ -147,8 +232,8 @@ fn match_grain(ctx: &EffectCtx, mut b: Buf) -> Buf { } } }); - if view == 0 { - crate::noise::preview_compose(ctx, &mut b, &orig); + if let Some(orig) = &orig { + crate::noise::preview_compose(ctx, &mut b, orig); } b } @@ -306,6 +391,63 @@ mod tests { img } + #[test] + fn boxed_grain_stats_match_the_masked_ones() { + // Noisy image with alpha holes; the boxes cover overlapping, edge-adjacent and + // bottom-right corner cases (clamped crops). + let mut img = noisy(64, 48, 0.2, 9); + for y in 0..img.height { + for x in 0..img.width { + if (x / 7 + y / 5) % 6 == 0 { + let mut p = img.get(x as i64, y as i64); + p[3] = 0.0; + img.set(x, y, p); + } + } + } + let boxes = [(3usize, 4usize, 9usize), (8, 6, 9), (40, 20, 12), (39, 21, 12), (55, 39, 9)]; + let w = img.width as usize; + let mut mask = vec![false; img.data.len()]; + for &(x, y, s) in &boxes { + for yy in y..y + s { + for xx in x..x + s { + mask[yy * w + xx] = true; + } + } + } + let masked = grain_stats_masked(&img, Some(&mask)); + let boxed = grain_stats_boxes(&img, &boxes); + for k in 0..3 { + assert!((masked.std[k] - boxed.std[k]).abs() < 1e-5, "{k}: {masked:?} vs {boxed:?}"); + } + assert!((masked.size - boxed.size).abs() <= 0.05 * masked.size.max(1.0), "size: {masked:?} vs {boxed:?}"); + // A denser grid where every box overlaps its neighbours (mask dedup across boxes). + let img2 = noisy(96, 64, 0.15, 21); + let mut boxes2 = Vec::new(); + for gy in 0..5 { + for gx in 0..6 { + boxes2.push((gx * 11 + (gy % 3) * 4, gy * 10 + gx % 2, 12)); + } + } + let w2 = img2.width as usize; + let mut mask2 = vec![false; img2.data.len()]; + for &(x, y, s) in &boxes2 { + for yy in y..y + s { + for xx in x..x + s { + mask2[yy * w2 + xx] = true; + } + } + } + let masked2 = grain_stats_masked(&img2, Some(&mask2)); + let boxed2 = grain_stats_boxes(&img2, &boxes2); + for k in 0..3 { + assert!((masked2.std[k] - boxed2.std[k]).abs() < 1e-5, "{k}: {masked2:?} vs {boxed2:?}"); + } + assert!((masked2.size - boxed2.size).abs() <= 0.05 * masked2.size.max(1.0), "size: {masked2:?} vs {boxed2:?}"); + // No boxes measures the whole image, like no mask. + assert_eq!(grain_stats_boxes(&img, &[]), grain_stats(&img)); + } + #[test] fn match_grain_transfers_grain_strength() { let flat = Image::filled(48, 48, [0.5, 0.5, 0.5, 1.0]); diff --git a/crates/effects/src/util.rs b/crates/effects/src/util.rs index 1527e221f..f22a9885f 100644 --- a/crates/effects/src/util.rs +++ b/crates/effects/src/util.rs @@ -6,6 +6,10 @@ use effectcraft_color::{luminance, rgb_to_hsl}; use effectcraft_raster::{Image, Px}; use rayon::prelude::*; +/// Below this many pixels, `Plane::transpose` and `Plane::map_rows` run on the calling thread: +/// the rayon dispatch costs more than the work on small crops (the Match Grain sample boxes). +const PAR_MIN: usize = 4096; + /// A single-channel `f32` image (row-major). #[derive(Clone, Debug, Default, PartialEq)] pub struct Plane { @@ -62,6 +66,15 @@ impl Plane { pub fn transpose(&self) -> Plane { let (w, h) = (self.w, self.h); let mut out = Plane::new(h, w); + if w.saturating_mul(h) < PAR_MIN { + // Small planes: the rayon dispatch costs more than the copy itself. + for (x, col) in out.data.chunks_mut(h.max(1)).enumerate() { + for y in 0..h { + col[y] = self.data[y * w + x]; + } + } + return out; + } out.data.par_chunks_mut(h.max(1)).enumerate().for_each(|(x, col)| { for y in 0..h { col[y] = self.data[y * w + x]; @@ -75,6 +88,11 @@ impl Plane { if self.w == 0 { return out; } + if self.w.saturating_mul(self.h) < PAR_MIN { + // Small planes: the rayon dispatch costs more than the rows themselves. + out.data.chunks_mut(self.w).zip(self.data.chunks(self.w)).for_each(|(o, s)| f(s, o)); + return out; + } out.data.par_chunks_mut(self.w).zip(self.data.par_chunks(self.w)).for_each(|(o, s)| f(s, o)); out }