AV1: decode tiles serially when parallel tile metadata copies would be huge

crates/av1/src/decoder.rs

@@ -777,6 +777,14 @@ fn decode_frame(job: &FrameJob, pool: &Pool, stats: &mut DecodeStats) -> Result<
     Ok((rf, pic))
 }
 
+/// Bytes all parallel tile states may hold of whole-frame CDEF and restoration metadata; past it
+/// the tiles decode one after another on the frame's own metadata.
+const TILE_METADATA_BUDGET: usize = 256 << 20;
+
+fn tile_metadata_fits(tiles: usize, per_tile: usize) -> bool {
+    tiles.checked_mul(per_tile).is_some_and(|n| n <= TILE_METADATA_BUDGET)
+}
+
 /// Decode the tiles of a frame (tile number, data), in parallel when several; returns the final
 /// CDFs of tile context_update_tile_id.
 fn decode_tiles(pool: &Pool, fs: &mut FrameState, cdfs: &Cdfs, tiles: &[(usize, Vec<u8>)]) -> Result<Option<Box<Cdfs>>> {
@@ -790,7 +798,7 @@ fn decode_tiles(pool: &Pool, fs: &mut FrameState, cdfs: &Cdfs, tiles: &[(usize,
     };
     // Intra block copy reads the current frame through the tile's own buffer: keep whole-frame
     // buffers (tiles one after another) for it.
-    if tiles.len() > 1 && pool.is_parallel() && !fs.fh.allow_intrabc {
+    if tiles.len() > 1 && pool.is_parallel() && !fs.fh.allow_intrabc && tile_metadata_fits(tiles.len(), fs.tile_metadata_bytes()) {
         let mut states: Vec<TileState> = tiles
             .iter()
             .map(|(num, _)| {
@@ -1075,6 +1083,14 @@ mod guard_tests {
 #[cfg(test)]
 mod budget_tests {
     use super::*;
+
+    #[test]
+    fn tile_metadata_copies_are_budgeted() {
+        assert!(tile_metadata_fits(64, 1 << 20));
+        assert!(!tile_metadata_fits(4096, 1 << 20));
+        assert!(!tile_metadata_fits(usize::MAX, 2));
+    }
+
     use deckcraft_bitstream::budget::DECODE_MEMORY_BUDGET;
 
     fn color(mono: bool) -> crate::header::ColorConfig {

crates/av1/src/state.rs

@@ -253,6 +253,13 @@ impl FrameState {
         self.lr = t.lr;
     }
 
+    /// Bytes of CDEF and loop-restoration metadata each parallel tile state copies whole.
+    pub fn tile_metadata_bytes(&self) -> usize {
+        let lr = &self.lr;
+        // 1 (type) + 6 (Wiener) + 1 (SGR set) + 2 (SGR weights) bytes per unit.
+        self.cdef.len() + lr.lr_type.iter().map(|v| v.len() * 10).sum::<usize>()
+    }
+
     /// Private buffers for the tile covering mode info rows [r0, r1) x columns [c0, c1); tiles
     /// on the right / bottom frame edge also cover the allocation margins.
     pub fn tile_state(&self, r0: usize, r1: usize, c0: usize, c1: usize) -> TileState {

crates/ui-egui/src/panels/notes.rs

@@ -8,7 +8,7 @@ use std::sync::Arc;
 
 use deckcraft_model::edit;
 use deckcraft_model::text::{Bullet, Paragraph, RunProps, Strike, TextBody};
-use egui::text::{Galley, LayoutJob, TextFormat};
+use egui::text::{CCursor, Galley, LayoutJob, TextFormat};
 use egui::{Align2, Color32, Stroke, Ui, vec2};
 
 use crate::theme;
@@ -210,30 +210,16 @@ pub fn editor(
     out
 }
 
-/// The (min y, max y) of the row holding char index `at`; `walk` (row index, chars through that
-/// row) carries over between calls, so successive non-decreasing `at`s cost one pass in all.
-fn row_span_at(galley: &Galley, walk: &mut (usize, usize), at: usize) -> (f32, f32) {
-    while walk.1 <= at && walk.0 + 1 < galley.rows.len() {
-        walk.0 += 1;
-        walk.1 += galley.rows[walk.0].char_count_including_newline().0;
-    }
-    galley.rows.get(walk.0).map_or((0.0, 0.0), |r| (r.min_y(), r.max_y()))
-}
-
 /// Bullets and numbers at the start of each paragraph's first line of `galley` (laid out from
 /// `body`), drawn at `origin`.
 fn paint_bullets(painter: &egui::Painter, body: &TextBody, galley: &Galley, origin: egui::Pos2, size: f32, color: Color32) {
     let k = size / 12.0;
     let mut at = 0usize;
-    // Paragraph starts only grow, so one forward walk over the rows finds each start's row
-    // (`pos_from_cursor` would rescan from the top for every bullet).
-    let mut walk = (0usize, galley.rows.first().map_or(0, |r| r.char_count_including_newline().0));
     for (p, bullet) in body.paragraphs.iter().zip(bullets(body)) {
         if let Some(b) = bullet {
-            let (min_y, max_y) = row_span_at(galley, &mut walk, at);
-            let (center_y, height) = ((min_y + max_y) / 2.0, max_y - min_y);
-            let pos = origin + vec2(px(indents(p).0, k), center_y);
-            let font = theme::font(height.clamp(size * 0.75, size * 2.0) * 0.8);
+            let row = galley.pos_from_cursor(CCursor::new(at));
+            let pos = origin + vec2(px(indents(p).0, k), row.center().y);
+            let font = theme::font(row.height().clamp(size * 0.75, size * 2.0) * 0.8);
             painter.text(pos, Align2::LEFT_CENTER, b, font, color);
         }
         at += p.char_len() + 1;
@@ -255,7 +241,6 @@ mod tests {
     #![allow(clippy::unwrap_used, clippy::expect_used)]
 
     use deckcraft_model::text::{ParaProps, Run};
-    use egui::text::CCursor;
 
     use super::*;
 
@@ -332,23 +317,6 @@ mod tests {
         assert!(wrapped.iter().all(|r| (r.pos.x - 22.5).abs() < 1.0), "wrapped lines align with the text");
     }
 
-    #[test]
-    fn row_walk_matches_cursor_lookup_at_paragraph_starts() {
-        let ctx = egui::Context::default();
-        let body = notes();
-        let mut laid = None;
-        let mut out = ctx.run_ui(Default::default(), |ui| laid = Some(galley(ui, &body, 12.0, Color32::BLACK, 300.0)));
-        out.textures_delta.clear();
-        let g = laid.unwrap();
-        let mut walk = (0usize, g.rows.first().map_or(0, |r| r.char_count_including_newline().0));
-        let mut at = 0usize;
-        for p in &body.paragraphs {
-            let want = g.pos_from_cursor(CCursor::new(at));
-            assert_eq!(row_span_at(&g, &mut walk, at), (want.min.y, want.max.y), "paragraph at char {at}");
-            at += p.char_len() + 1;
-        }
-    }
-
     #[test]
     fn typing_keeps_the_formatting_around_it() {
         let mut d = Draft::new(&notes());