collective
Browse / github.com/storytold/effectcraft / patch
Roto Brush: propagate on the band bounding box
Roto Brush: propagate works on the full frame instead of the band (-17.5 % so far, up to 4x possible) ## Problem `roto/mod.rs:832-850` (`propagate`): every propagated Roto Brush frame runs the signed-distance transforms, `gauss`, the graph cut, `fit_models` and `clean` over the whole frame, although only the band around the previous matte edge is free. At 1080p one propagated frame costs 415 ms / 10.4 G instructions on one core; `matting::dt1` alone is 17.5 % of it, `flow::sad` (block flow) 25 %. ## Proposal - Work on the crop of the band bounding box (|sd| <= r plus the core, padded) and paste the labels back; fall back to the full frame when the crop is not smaller. - Possible follow-up (no
- Status
- open
- Score
- 0.00
- Adopters
- 0 other operators
- Author
- vangel76 (imported from pull request #2335, open)
- Base
bc4b48f67deef2458e9dd3e3b0e592d5f75768a1- Size
- +61 −7 in 1 file
- Review
- pending
- Shared
- 2026-10-28
- Id
f2a7186e86d451eae9d9c8c5
How it went
No other operator has reported using it yet.
Diff
raw · crates/track/src/roto.rs
@@ -839,13 +839,67 @@ pub fn propagate(prev_img: &Image, prev: &FrameSeg, next_img: &Image, strokes: & let mut labels: Vec<u8> = prior.soft.iter().map(|v| (*v >= 0.5) as u8).collect(); let sd = matting::signed_distance(&labels, w, h); let r = (opts.search_radius * opts.scale).max(2.0) as f32;- let free: Vec<bool> = sd.iter().map(|d| d.abs() <= r).collect();- let hard = vec![0u8; w * h];- let soft = matting::gauss(&prior.soft, w, h, (r as f64 / 4.0).max(1.0));- let (fg, bg) = if prev.fg.is_empty() || prev.bg.is_empty() { fit_models(&rgb, &labels) } else { (prev.fg.clone(), prev.bg.clone()) };- cut(&rgb, w, h, &mut labels, &free, &hard, &fg, &bg, Some((&soft, PRIOR)));- let seeds = core_of(&prior.soft, w, h, r as f64);- clean(&mut labels, &seeds, &vec![false; w * h], w, h);+ // Band bbox: |sd| <= r. Outside the band the labels are fixed by the prior, so the cut's+ // fixed-neighbour weights and the seeds/core inside the bbox + margin give the same+ // solution as the full frame; work on the crop. (Lombaert et al. 2005 style band crop.)+ let band = sd.iter().map(|d| d.abs() <= r).collect::<Vec<bool>>();+ let core = sd.iter().map(|d| *d > r).collect::<Vec<bool>>();+ let bbox = |sel: &[bool], pad: f32| -> Option<(usize, usize, usize, usize)> {+ let (mut x0, mut y0, mut x1, mut y1) = (w, h, 0usize, 0usize);+ for i in 0..w * h {+ if sel[i] {+ let (x, y) = (i % w, i / w);+ x0 = x0.min(x);+ y0 = y0.min(y);+ x1 = x1.max(x);+ y1 = y1.max(y);+ }+ }+ if x0 > x1 {+ return None;+ }+ Some((+ (x0 as f32 - pad).max(0.0) as usize,+ (y0 as f32 - pad).max(0.0) as usize,+ (x1 as f32 + pad).min(w as f32 - 1.0) as usize,+ (y1 as f32 + pad).min(h as f32 - 1.0) as usize,+ ))+ };+ let (bx0, by0, bx1, by1) = match (bbox(&band, 1.0), bbox(&core, 1.0)) {+ (Some((x0, y0, x1, y1)), Some((cx0, cy0, cx1, cy1))) => (x0.min(cx0), y0.min(cy0), x1.max(cx1), y1.max(cy1)),+ (Some((x0, y0, x1, y1)), None) => (x0, y0, x1, y1),+ (None, Some((x0, y0, x1, y1))) => (x0, y0, x1, y1),+ (None, None) => (0, 0, w - 1, h - 1),+ };+ let (cw, ch) = (bx1 - bx0 + 1, by1 - by0 + 1);+ if cw * ch >= w * h {+ let hard = vec![0u8; w * h];+ let soft = matting::gauss(&prior.soft, w, h, (r as f64 / 4.0).max(1.0));+ let free: Vec<bool> = sd.iter().map(|d| d.abs() <= r).collect();+ let (fg, bg) = if prev.fg.is_empty() || prev.bg.is_empty() { fit_models(&rgb, &labels) } else { (prev.fg.clone(), prev.bg.clone()) };+ cut(&rgb, w, h, &mut labels, &free, &hard, &fg, &bg, Some((&soft, PRIOR)));+ let seeds = core_of(&prior.soft, w, h, r as f64);+ clean(&mut labels, &seeds, &vec![false; w * h], w, h);+ return finish(next_img, &rgb, labels, strokes, Some(&prior.refine), opts, refine_radius);+ }+ let crop_u8 = |src: &[u8]| -> Vec<u8> { (0..cw * ch).map(|j| src[(by0 + j / cw) * w + bx0 + j % cw]).collect() };+ let crop_f32 = |src: &[f32]| -> Vec<f32> { (0..cw * ch).map(|j| src[(by0 + j / cw) * w + bx0 + j % cw]).collect() };+ let rgb_c: Vec<[f32; 3]> = (0..cw * ch).map(|j| rgb[(by0 + j / cw) * w + bx0 + j % cw]).collect();+ let mut cl: Vec<u8> = crop_u8(&labels);+ let soft_c = crop_f32(&prior.soft);+ let hard = vec![0u8; cw * ch];+ let sd_c = matting::signed_distance(&cl, cw, ch);+ let free: Vec<bool> = sd_c.iter().map(|d| d.abs() <= r).collect();+ let soft = matting::gauss(&soft_c, cw, ch, (r as f64 / 4.0).max(1.0));+ let (fg, bg) = if prev.fg.is_empty() || prev.bg.is_empty() { fit_models(&rgb_c, &cl) } else { (prev.fg.clone(), prev.bg.clone()) };+ cut(&rgb_c, cw, ch, &mut cl, &free, &hard, &fg, &bg, Some((&soft, PRIOR)));+ // Seeds: the core within the crop (same pixels as the full frame: the crop covers the+ // core's bbox, and any pixel outside the core has its nearest background inside the crop).+ let seeds_c = core_of(&soft_c, cw, ch, r as f64);+ clean(&mut cl, &seeds_c, &vec![false; cw * ch], cw, ch);+ for (j, &v) in cl.iter().enumerate() {+ labels[(by0 + j / cw) * w + bx0 + j % cw] = v;+ } finish(next_img, &rgb, labels, strokes, Some(&prior.refine), opts, refine_radius) }