Feat: document time stretching

.github/workflows/build-windows.yml

@@ -113,6 +113,7 @@ jobs:
 
       - name: Prepare plugin artifacts
         if: inputs.build-packages
+        shell: bash
         run: |
           mkdir -p staging/clap staging/vst3
           cp -R target/bundled/cagire-plugins.clap staging/clap/

Cargo.lock

@@ -1810,7 +1810,6 @@ dependencies = [
 [[package]]
 name = "doux"
 version = "0.0.7"
-source = "git+https://github.com/sova-org/doux#b2acd4d2737e0a981635266bf22926215453380e"
 dependencies = [
  "arc-swap",
  "clap",

Cargo.toml

@@ -51,7 +51,7 @@ cagire-forth = { path = "crates/forth" }
 cagire-markdown = { path = "crates/markdown" }
 cagire-project = { path = "crates/project" }
 cagire-ratatui = { path = "crates/ratatui" }
-doux = { git = "https://github.com/sova-org/doux", features = ["native", "soundfont"] }
+doux = { path = "/Users/bubo/doux", features = ["native", "soundfont"] }
 rusty_link = "0.4"
 ratatui = "0.30"
 crossterm = "0.29"

crates/forth/src/types.rs

@@ -63,6 +63,7 @@ pub struct StepContext<'a> {
     pub speed: f64,
     pub fill: bool,
     pub nudge_secs: f64,
+    pub sr: f64,
     pub cc_access: Option<&'a dyn CcAccess>,
     pub speed_key: &'a str,
     pub mouse_x: f64,

crates/forth/src/vm.rs

@@ -302,6 +302,7 @@ impl Forth {
                 &resolved_params,
                 ctx.step_duration(),
                 delta_secs,
+                ctx.sr,
                 outputs,
             );
             Ok(resolved_sound_val.map(|v| v.into_owned()))
@@ -1542,7 +1543,7 @@ impl Forth {
                             .unwrap_or(0);
                         let dev =
                             get_int("dev").map(|d| d.clamp(0, 3) as u8).unwrap_or(0);
-                        let delta_suffix = if delta_secs > 0.0 {
+                        let delta_suffix = if delta_secs.abs() > 1e-9 {
                             format!("/delta/{delta_secs}")
                         } else {
                             String::new()
@@ -1741,6 +1742,7 @@ fn emit_output(
     params: &[(&str, String)],
     step_duration: f64,
     nudge_secs: f64,
+    sr: f64,
     outputs: &mut Vec<String>,
 ) {
     use std::fmt::Write;
@@ -1748,6 +1750,7 @@ fn emit_output(
     out.push('/');
 
     let has_dur = params.iter().any(|(k, _)| *k == "dur");
+    let has_release = params.iter().any(|(k, _)| *k == "release");
     let delaytime_idx = params.iter().position(|(k, _)| *k == "delaytime");
 
     if let Some(s) = sound {
@@ -1772,11 +1775,12 @@ fn emit_output(
         }
     }
 
-    if nudge_secs > 0.0 {
+    if nudge_secs.abs() > 1e-9 {
         if !out.ends_with('/') {
             out.push('/');
         }
-        let _ = write!(&mut out, "delta/{nudge_secs}");
+        let delta_ticks = (nudge_secs * sr).round() as i64;
+        let _ = write!(&mut out, "delta/{delta_ticks}");
     }
 
     if !has_dur {
@@ -1786,6 +1790,13 @@ fn emit_output(
         let _ = write!(&mut out, "dur/{}", step_duration * 4.0);
     }
 
+    if !has_release {
+        if !out.ends_with('/') {
+            out.push('/');
+        }
+        let _ = write!(&mut out, "release/{}", 12.0 * step_duration);
+    }
+
     if sound.is_some() && delaytime_idx.is_none() {
         if !out.ends_with('/') {
             out.push('/');

crates/forth/src/words/sound.rs

@@ -166,6 +166,16 @@ pub(super) const WORDS: &[Word] = &[
         compile: Param,
         varargs: true,
     },
+    Word {
+        name: "stretch",
+        aliases: &[],
+        category: "Sample",
+        stack: "(v.. --)",
+        desc: "Time stretch factor (pitch-independent)",
+        example: "2 stretch",
+        compile: Param,
+        varargs: true,
+    },
     Word {
         name: "begin",
         aliases: &[],

crates/ratatui/src/theme/mod.rs

@@ -30,6 +30,7 @@ pub mod transform;
 
 use ratatui::style::Color;
 use std::cell::RefCell;
+use std::rc::Rc;
 
 /// Entry in the theme registry: id, display label, and palette constructor.
 pub struct ThemeEntry {
@@ -66,17 +67,17 @@ pub const THEMES: &[ThemeEntry] = &[
 ];
 
 thread_local! {
-    static CURRENT_THEME: RefCell<ThemeColors> = RefCell::new(build::build(&(THEMES[0].palette)()));
+    static CURRENT_THEME: RefCell<Rc<ThemeColors>> = RefCell::new(Rc::new(build::build(&(THEMES[0].palette)())));
 }
 
-/// Return the current thread-local theme.
-pub fn get() -> ThemeColors {
-    CURRENT_THEME.with(|t| t.borrow().clone())
+/// Return the current thread-local theme (cheap Rc clone, not a deep copy).
+pub fn get() -> Rc<ThemeColors> {
+    CURRENT_THEME.with(|t| Rc::clone(&t.borrow()))
 }
 
 /// Set the current thread-local theme.
 pub fn set(theme: ThemeColors) {
-    CURRENT_THEME.with(|t| *t.borrow_mut() = theme);
+    CURRENT_THEME.with(|t| *t.borrow_mut() = Rc::new(theme));
 }
 
 /// Complete set of resolved colors for all UI components.

docs/engine/samples.md

@@ -50,6 +50,7 @@ snare sound  0.5 speed .         ( play snare at half speed )
 | `slice` | 1+ | Divide sample into N equal slices |
 | `pick` | 0+ | Select which slice to play (0-indexed, wraps) |
 | `speed` | any | Playback speed multiplier |
+| `stretch` | 0+ | Time-stretch factor (pitch-independent) |
 | `freq` | Hz | Base frequency for pitch tracking |
 | `fit` | seconds | Stretch/compress sample to fit duration |
 | `cut` | 0+ | Choke group |
@@ -105,6 +106,24 @@ crow sound -1 speed .              ( play backwards at nominal speed )
 crow sound -4 speed .              ( play backwards, 4 times faster )
 ```
 
+## Time Stretching
+
+The `stretch` parameter changes sample duration without affecting pitch, using a phase vocoder algorithm. This contrasts with `speed`, which changes both tempo and pitch together.
+
+```forth
+kick sound 2 stretch .             ( twice as long, same pitch )
+kick sound 0.5 stretch .           ( half as long, same pitch )
+kick sound 0 stretch .             ( freeze — holds at current position )
+```
+
+Combine with `slice` and `pick` for pitch-locked breakbeat manipulation:
+
+```forth
+break sound 8 slice step pick 2 stretch .   ( sliced break, stretched x2, original pitch )
+```
+
+Reverse playback is not available with `stretch` — use `speed` for that.
+
 ## Fitting to Duration
 
 The `fit` parameter stretches or compresses a sample to match a target duration in seconds. This adjusts speed automatically.

plugins/cagire-plugins/Cargo.toml

@@ -14,7 +14,7 @@ cagire = { path = "../..", default-features = false, features = ["block-renderer
 cagire-forth = { path = "../../crates/forth" }
 cagire-project = { path = "../../crates/project" }
 cagire-ratatui = { path = "../../crates/ratatui" }
-doux = { git = "https://github.com/sova-org/doux", features = ["native", "soundfont"] }
+doux = { path = "/Users/bubo/doux", features = ["native", "soundfont"] }
 nih_plug = { git = "https://github.com/robbert-vdh/nih-plug", features = ["standalone"] }
 nih_plug_egui = { git = "https://github.com/robbert-vdh/nih-plug" }
 egui_ratatui = "2.1"

src/app/mod.rs

@@ -14,7 +14,7 @@ use arc_swap::ArcSwap;
 use parking_lot::Mutex;
 use rand::rngs::StdRng;
 use rand::SeedableRng;
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::sync::{Arc, LazyLock};
 
 use cagire_ratatui::CompletionCandidate;
@@ -69,6 +69,7 @@ pub struct App {
     pub sample_browser: Option<SampleBrowserState>,
     pub midi: MidiState,
     pub plugin_mode: bool,
+    pub dict_keys: HashSet<String>,
 }
 
 impl Default for App {
@@ -126,6 +127,7 @@ impl App {
             sample_browser: None,
             midi: MidiState::new(),
             plugin_mode,
+            dict_keys: HashSet::new(),
         }
     }
 

src/app/scripting.rs

@@ -34,6 +34,7 @@ impl App {
             speed,
             fill: false,
             nudge_secs: 0.0,
+            sr: 0.0,
             cc_access: None,
             speed_key: "",
             mouse_x: 0.5,
@@ -148,7 +149,9 @@ impl App {
         }
         let ctx = self.create_step_context(0, link);
         match self.script_engine.evaluate(prelude, &ctx) {
-            Ok(_) => {}
+            Ok(_) => {
+                self.dict_keys = self.dict.lock().keys().cloned().collect();
+            }
             Err(e) => {
                 let fallback = format!("Bank {}", bank + 1);
                 let bank_name = self.project_state.project.banks[bank]
@@ -201,6 +204,7 @@ impl App {
                 }
             }
         }
+        self.dict_keys = self.dict.lock().keys().cloned().collect();
         self.ui.flash("Preludes evaluated", 150, FlashKind::Info);
     }
 

src/bin/desktop/main.rs

@@ -616,7 +616,6 @@ fn load_icon() -> egui::IconData {
 }
 
 fn main() -> eframe::Result<()> {
-    #[cfg(unix)]
     cagire::engine::realtime::lock_memory();
 
     let args = Args::parse();

src/engine/audio.rs

@@ -264,10 +264,6 @@ use cpal::Stream;
 use crossbeam_channel::{Receiver, Sender};
 #[cfg(feature = "cli")]
 use doux::{Engine, EngineMetrics};
-#[cfg(feature = "cli")]
-use std::collections::VecDeque;
-#[cfg(feature = "cli")]
-use std::sync::Mutex;
 
 #[cfg(feature = "cli")]
 use super::AudioCommand;
@@ -360,8 +356,7 @@ pub fn build_stream(
     let registry = Arc::clone(&engine.sample_registry);
 
     const INPUT_BUFFER_SIZE: usize = 8192;
-    let input_buffer: Arc<Mutex<VecDeque<f32>>> =
-        Arc::new(Mutex::new(VecDeque::with_capacity(INPUT_BUFFER_SIZE)));
+    let (input_producer, input_consumer) = HeapRb::<f32>::new(INPUT_BUFFER_SIZE).split();
 
     let input_device = config
         .input_device
@@ -399,17 +394,12 @@ pub fn build_stream(
             input_cfg.channels(),
             input_cfg.sample_rate()
         );
-        let buf = Arc::clone(&input_buffer);
+        let mut input_producer = input_producer;
         let stream = dev
             .build_input_stream(
                 &input_cfg.into(),
                 move |data: &[f32], _| {
-                    let mut b = buf.lock().unwrap();
-                    b.extend(data.iter().copied());
-                    let excess = b.len().saturating_sub(INPUT_BUFFER_SIZE);
-                    if excess > 0 {
-                        drop(b.drain(..excess));
-                    }
+                    input_producer.push_slice(data);
                 },
                 {
                     let device_lost = Arc::clone(&device_lost);
@@ -436,15 +426,18 @@ pub fn build_stream(
     let mut cmd_buffer = String::with_capacity(256);
     let mut rt_set = false;
     let mut live_scratch = vec![0.0f32; 4096];
-    let input_buf_clone = Arc::clone(&input_buffer);
+    let mut input_consumer = input_consumer;
 
     let stream = device
         .build_output_stream(
             &stream_config,
             move |data: &mut [f32], _| {
                 if !rt_set {
-                    super::realtime::set_realtime_priority();
+                    let ok = super::realtime::set_realtime_priority();
                     rt_set = true;
+                    if !ok {
+                        super::realtime::warn_no_rt("audio");
+                    }
                 }
 
                 let buffer_samples = data.len() / channels;
@@ -488,29 +481,28 @@ pub fn build_stream(
                 if live_scratch.len() < stereo_len {
                     live_scratch.resize(stereo_len, 0.0);
                 }
-                let mut buf = input_buf_clone.lock().unwrap();
                 match input_channels {
                     0 => {
                         live_scratch[..stereo_len].fill(0.0);
                     }
                     1 => {
                         for i in 0..buffer_samples {
-                            let s = buf.pop_front().unwrap_or(0.0);
+                            let s = input_consumer.try_pop().unwrap_or(0.0);
                             live_scratch[i * 2] = s;
                             live_scratch[i * 2 + 1] = s;
                         }
                     }
                     2 => {
                         for sample in &mut live_scratch[..stereo_len] {
-                            *sample = buf.pop_front().unwrap_or(0.0);
+                            *sample = input_consumer.try_pop().unwrap_or(0.0);
                         }
                     }
                     _ => {
                         for i in 0..buffer_samples {
-                            let l = buf.pop_front().unwrap_or(0.0);
-                            let r = buf.pop_front().unwrap_or(0.0);
+                            let l = input_consumer.try_pop().unwrap_or(0.0);
+                            let r = input_consumer.try_pop().unwrap_or(0.0);
                             for _ in 2..input_channels {
-                                buf.pop_front();
+                                input_consumer.try_pop();
                             }
                             live_scratch[i * 2] = l;
                             live_scratch[i * 2 + 1] = r;
@@ -518,11 +510,10 @@ pub fn build_stream(
                     }
                 }
                 // Discard excess if input produced more than we consumed
-                let excess = buf.len().saturating_sub(INPUT_BUFFER_SIZE / 2);
-                if excess > 0 {
-                    drop(buf.drain(..excess));
+                let excess = input_consumer.occupied_len().saturating_sub(INPUT_BUFFER_SIZE / 2);
+                for _ in 0..excess {
+                    input_consumer.try_pop();
                 }
-                drop(buf);
 
                 engine.metrics.load.set_buffer_time(buffer_time_ns);
                 engine.process_block(data, &[], &live_scratch[..stereo_len]);

src/engine/dispatcher.rs

@@ -6,7 +6,7 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use super::link::LinkState;
-use super::realtime::{precise_sleep_us, set_realtime_priority};
+use super::realtime::{precise_sleep_us, set_realtime_priority, warn_no_rt};
 use super::sequencer::MidiCommand;
 use super::timing::SyncTime;
 
@@ -55,10 +55,8 @@ pub fn dispatcher_loop(
     link: Arc<LinkState>,
 ) {
     let has_rt = set_realtime_priority();
-
-    #[cfg(target_os = "linux")]
     if !has_rt {
-        eprintln!("[cagire] Warning: Could not set realtime priority for dispatcher thread.");
+        warn_no_rt("dispatcher");
     }
 
     let mut queue: BinaryHeap<TimedMidiCommand> = BinaryHeap::with_capacity(256);

src/engine/realtime.rs

@@ -148,6 +148,17 @@ pub fn set_realtime_priority() -> bool {
     false
 }
 
+#[cfg(target_os = "linux")]
+pub fn warn_no_rt(thread_name: &str) {
+    eprintln!(
+        "[cagire] Warning: No realtime priority for {thread_name} thread. \
+         Add user to 'audio' group and configure rtprio limits."
+    );
+}
+
+#[cfg(not(target_os = "linux"))]
+pub fn warn_no_rt(_thread_name: &str) {}
+
 /// High-precision sleep using clock_nanosleep on Linux.
 /// Uses monotonic clock for jitter-free sleeping.
 #[cfg(target_os = "linux")]

src/engine/sequencer.rs

@@ -1007,6 +1007,7 @@ impl SequencerState {
                                 speed: speed_mult,
                                 fill,
                                 nudge_secs,
+                                sr,
                                 cc_access: self.cc_access.as_deref(),
                                 speed_key,
                                 mouse_x,
@@ -1128,6 +1129,7 @@ impl SequencerState {
                     speed: speed_mult,
                     fill,
                     nudge_secs,
+                    sr,
                     cc_access: self.cc_access.as_deref(),
                     speed_key: "",
                     mouse_x,
@@ -1266,13 +1268,16 @@ fn sequencer_loop(
 ) {
     use std::sync::atomic::Ordering;
 
-    set_realtime_priority();
+    let has_rt = set_realtime_priority();
+    if !has_rt {
+        super::realtime::warn_no_rt("sequencer");
+    }
 
     let rng: Rng = Arc::new(Mutex::new(StdRng::seed_from_u64(0)));
     let mut seq_state = SequencerState::new(variables, dict, rng, cc_access);
 
-    // Lookahead window: ~20ms expressed in beats, recomputed each tick
-    const LOOKAHEAD_SECS: f64 = 0.02;
+    // Lookahead window: 20ms normally, 40ms on Linux without RT to compensate for jitter
+    let lookahead_secs: f64 = if cfg!(target_os = "linux") && !has_rt { 0.04 } else { 0.02 };
     // Wake cadence: how long to sleep between scheduling passes
     const WAKE_INTERVAL: std::time::Duration = std::time::Duration::from_millis(3);
 
@@ -1302,7 +1307,7 @@ fn sequencer_loop(
         let tempo = state.tempo();
 
         let lookahead_beats = if tempo > 0.0 {
-            LOOKAHEAD_SECS * tempo / 60.0
+            lookahead_secs * tempo / 60.0
         } else {
             0.0
         };

src/main.rs

@@ -76,7 +76,6 @@ fn main() -> io::Result<()> {
     #[cfg(unix)]
     let mut stderr_pipe = redirect_stderr();
 
-    #[cfg(unix)]
     engine::realtime::lock_memory();
 
     let args = Args::parse();

src/views/main_view.rs

@@ -75,7 +75,6 @@ fn render_top_layout(
         idx += 1;
     }
     if has_preview {
-        let user_words: HashSet<String> = app.dict.lock().keys().cloned().collect();
         let has_prelude = !app.project_state.project.prelude.trim().is_empty()
                     || !app.project_state.project.banks[app.editor_ctx.bank]
                         .prelude
@@ -84,10 +83,10 @@ fn render_top_layout(
         if has_prelude {
             let [script_area, prelude_area] =
                 Layout::horizontal([Constraint::Fill(1), Constraint::Fill(1)]).areas(areas[idx]);
-            render_script_preview(frame, app, snapshot, &user_words, script_area);
-            render_prelude_preview(frame, app, &user_words, prelude_area);
+            render_script_preview(frame, app, snapshot, &app.dict_keys, script_area);
+            render_prelude_preview(frame, app, &app.dict_keys, prelude_area);
         } else {
-            render_script_preview(frame, app, snapshot, &user_words, areas[idx]);
+            render_script_preview(frame, app, snapshot, &app.dict_keys, areas[idx]);
         }
         idx += 1;
     }
@@ -186,19 +185,12 @@ fn render_viz_area(
         Orientation::Horizontal
     };
 
-    let user_words_once: Option<HashSet<String>> = if panels.iter().any(|p| matches!(p, VizPanel::Preview)) {
-        Some(app.dict.lock().keys().cloned().collect())
-    } else {
-        None
-    };
-
     for (panel, panel_area) in panels.iter().zip(areas.iter()) {
         match panel {
             VizPanel::Scope => render_scope(frame, app, *panel_area, orientation),
             VizPanel::Spectrum => render_spectrum(frame, app, *panel_area),
             VizPanel::Lissajous => render_lissajous(frame, app, *panel_area),
             VizPanel::Preview => {
-                let user_words = user_words_once.as_ref().expect("user_words initialized");
                 let has_prelude = !app.project_state.project.prelude.trim().is_empty()
                     || !app.project_state.project.banks[app.editor_ctx.bank]
                         .prelude
@@ -212,10 +204,10 @@ fn render_viz_area(
                         Layout::horizontal([Constraint::Fill(1), Constraint::Fill(1)])
                             .areas(*panel_area)
                     };
-                    render_script_preview(frame, app, snapshot, user_words, script_area);
-                    render_prelude_preview(frame, app, user_words, prelude_area);
+                    render_script_preview(frame, app, snapshot, &app.dict_keys, script_area);
+                    render_prelude_preview(frame, app, &app.dict_keys, prelude_area);
                 } else {
-                    render_script_preview(frame, app, snapshot, user_words, *panel_area);
+                    render_script_preview(frame, app, snapshot, &app.dict_keys, *panel_area);
                 }
             }
         }

src/views/render.rs

@@ -675,8 +675,7 @@ fn render_modal(
                 .render_centered(frame, term)
         }
         Modal::Editor => {
-            let user_words: HashSet<String> = app.dict.lock().keys().cloned().collect();
-            render_modal_editor(frame, app, snapshot, &user_words, term)
+            render_modal_editor(frame, app, snapshot, &app.dict_keys, term)
         }
         Modal::PatternProps {
             bank,

src/views/script_view.rs

@@ -1,5 +1,3 @@
-use std::collections::HashSet;
-
 use ratatui::layout::{Alignment, Constraint, Layout, Rect};
 use ratatui::style::Style;
 use ratatui::widgets::{Block, Borders, Paragraph};
@@ -47,7 +45,7 @@ fn render_editor(frame: &mut Frame, app: &App, snapshot: &SequencerSnapshot, are
     let editor_area = Rect::new(inner.x, inner.y, inner.width, editor_height);
     let hint_area = Rect::new(inner.x, inner.y + editor_height, inner.width, 1);
 
-    let user_words: HashSet<String> = app.dict.lock().keys().cloned().collect();
+    let user_words = &app.dict_keys;
 
     let trace = if app.ui.runtime_highlight && app.playback.playing {
         snapshot.script_trace()
@@ -77,7 +75,7 @@ fn render_editor(frame: &mut Frame, app: &App, snapshot: &SequencerSnapshot, are
             ),
             None => (Vec::new(), Vec::new(), Vec::new()),
         };
-        highlight::highlight_line_with_runtime(line, &exec, &sel, &res, &user_words)
+        highlight::highlight_line_with_runtime(line, &exec, &sel, &res, user_words)
     };
 
     app.script_editor.editor.render(frame, editor_area, &highlighter);
@@ -142,7 +140,6 @@ fn render_sidebar(frame: &mut Frame, app: &App, area: Rect) {
         idx += 1;
     }
     if has_prelude {
-        let user_words: HashSet<String> = app.dict.lock().keys().cloned().collect();
-        super::main_view::render_prelude_preview(frame, app, &user_words, areas[idx]);
+        super::main_view::render_prelude_preview(frame, app, &app.dict_keys, areas[idx]);
     }
 }

tests/forth/harness.rs

@@ -20,6 +20,7 @@ pub fn default_ctx() -> StepContext<'static> {
         speed: 1.0,
         fill: false,
         nudge_secs: 0.0,
+        sr: 48000.0,
         cc_access: None,
         speed_key: "__speed_0_0__",
         mouse_x: 0.5,

tests/forth/temporal.rs

@@ -144,7 +144,8 @@ fn at_single_delta() {
     let outputs = expect_outputs(r#"0.5 at "kick" snd ."#, 1);
     let deltas = get_deltas(&outputs);
     let step_dur = 0.125;
-    assert!(approx_eq(deltas[0], 0.5 * step_dur), "expected delta at 0.5 of step, got {}", deltas[0]);
+    let sr: f64 = 48000.0;
+    assert!(approx_eq(deltas[0], (0.5 * step_dur * sr).round()), "expected delta at 0.5 of step, got {}", deltas[0]);
 }
 
 #[test]
@@ -152,8 +153,9 @@ fn at_list_deltas() {
     let outputs = expect_outputs(r#"0 0.5 at "kick" snd ."#, 2);
     let deltas = get_deltas(&outputs);
     let step_dur = 0.125;
+    let sr: f64 = 48000.0;
     assert!(approx_eq(deltas[0], 0.0), "expected delta 0, got {}", deltas[0]);
-    assert!(approx_eq(deltas[1], 0.5 * step_dur), "expected delta at 0.5 of step, got {}", deltas[1]);
+    assert!(approx_eq(deltas[1], (0.5 * step_dur * sr).round()), "expected delta at 0.5 of step, got {}", deltas[1]);
 }
 
 #[test]
@@ -161,9 +163,10 @@ fn at_three_deltas() {
     let outputs = expect_outputs(r#"0 0.33 0.67 at "kick" snd ."#, 3);
     let deltas = get_deltas(&outputs);
     let step_dur = 0.125;
+    let sr: f64 = 48000.0;
     assert!(approx_eq(deltas[0], 0.0), "expected delta 0");
-    assert!((deltas[1] - 0.33 * step_dur).abs() < 0.001, "expected delta at 0.33 of step");
-    assert!((deltas[2] - 0.67 * step_dur).abs() < 0.001, "expected delta at 0.67 of step");
+    assert!(approx_eq(deltas[1], (0.33 * step_dur * sr).round()), "expected delta at 0.33 of step");
+    assert!(approx_eq(deltas[2], (0.67 * step_dur * sr).round()), "expected delta at 0.67 of step");
 }
 
 #[test]
@@ -234,10 +237,11 @@ fn arp_auto_subdivide() {
     assert!(approx_eq(notes[3], 71.0));
     let deltas = get_deltas(&outputs);
     let step_dur = 0.125;
+    let sr: f64 = 48000.0;
     assert!(approx_eq(deltas[0], 0.0));
-    assert!(approx_eq(deltas[1], 0.25 * step_dur));
-    assert!(approx_eq(deltas[2], 0.5 * step_dur));
-    assert!(approx_eq(deltas[3], 0.75 * step_dur));
+    assert!(approx_eq(deltas[1], (0.25 * step_dur * sr).round()));
+    assert!(approx_eq(deltas[2], (0.5 * step_dur * sr).round()));
+    assert!(approx_eq(deltas[3], (0.75 * step_dur * sr).round()));
 }
 
 #[test]
@@ -250,10 +254,11 @@ fn arp_with_explicit_at() {
     assert!(approx_eq(notes[3], 71.0));
     let deltas = get_deltas(&outputs);
     let step_dur = 0.125;
+    let sr: f64 = 48000.0;
     assert!(approx_eq(deltas[0], 0.0));
-    assert!(approx_eq(deltas[1], 0.25 * step_dur));
-    assert!(approx_eq(deltas[2], 0.5 * step_dur));
-    assert!(approx_eq(deltas[3], 0.75 * step_dur));
+    assert!(approx_eq(deltas[1], (0.25 * step_dur * sr).round()));
+    assert!(approx_eq(deltas[2], (0.5 * step_dur * sr).round()));
+    assert!(approx_eq(deltas[3], (0.75 * step_dur * sr).round()));
 }
 
 #[test]
@@ -273,10 +278,11 @@ fn arp_fewer_deltas_than_notes() {
     assert!(approx_eq(notes[3], 71.0));
     let deltas = get_deltas(&outputs);
     let step_dur = 0.125;
+    let sr: f64 = 48000.0;
     assert!(approx_eq(deltas[0], 0.0));
-    assert!(approx_eq(deltas[1], 0.5 * step_dur));
-    assert!(approx_eq(deltas[2], 0.0));           // wraps: 2 % 2 = 0
-    assert!(approx_eq(deltas[3], 0.5 * step_dur)); // wraps: 3 % 2 = 1
+    assert!(approx_eq(deltas[1], (0.5 * step_dur * sr).round()));
+    assert!(approx_eq(deltas[2], 0.0));                            // wraps: 2 % 2 = 0
+    assert!(approx_eq(deltas[3], (0.5 * step_dur * sr).round()));  // wraps: 3 % 2 = 1
 }
 
 #[test]