diff --git a/crates/engine/src/cmd/clip.rs b/crates/engine/src/cmd/clip.rs index 520e5377..b2fddb09 100644 --- a/crates/engine/src/cmd/clip.rs +++ b/crates/engine/src/cmd/clip.rs @@ -199,9 +199,7 @@ fn elastic(e: &mut Engine, p: &Value) -> Result { continue; } let out_len = soundcraft_time::to_samples(base.length as f64 * ratio).max(1); - let mut warp = base.clone(); - warp.stretch = ratio; - let Some(src) = super::more_util::render_stretched(s, "clip.elastic_properties", &warp, out_len)? else { continue }; + let Some(src) = super::more_util::render_stretched(s, "clip.elastic_properties", &base, out_len)? else { continue }; if orig.is_none() && let soundcraft_model::ClipContent::Audio { source, offset } = base.content { @@ -378,6 +376,45 @@ mod tests { assert_eq!(e.session().find_clip(ClipId(cid)).unwrap().1.length, len0); } + /// A clip on an Elastic track playing `clip_len` samples of a source that is silent before `tone_at`. + fn elastic_clip(source_len: usize, tone_at: usize, clip_len: i64) -> (crate::Engine, TrackId, ClipId) { + use soundcraft_model::{ChannelFormat, Clip, Session, TrackKind}; + let mut s = Session::default(); + let t = s.add_track(TrackKind::Audio, ChannelFormat::Mono, Some("Elastic")); + let samples = (0..source_len).map(|i| if i >= tone_at { (i as f32 * 0.2).sin() * 0.4 } else { 0.0 }).collect(); + let buf = soundcraft_audio_io::AudioBuffer { sample_rate: 48_000, channels: vec![samples] }; + let src = crate::io::add_source(&mut s, "Tone", buf, None, soundcraft_audio_io::FileFormat::Wav); + let cid = s.new_clip_id(); + crate::edit::place_clip(&mut s, t, Clip::audio(cid, "Clip", src, 0, 0, clip_len)); + let mut e = crate::Engine::new(s); + e.execute("track.elastic", &json!({"track": t.0, "algorithm": "polyphonic"})).unwrap(); + (e, t, cid) + } + + fn rendered_peak(e: &crate::Engine, t: TrackId, cid: ClipId) -> f32 { + let range = e.session().find_clip(cid).unwrap().1.range(); + soundcraft_mix::render_clips(e.session(), t, range).iter().flatten().fold(0.0, |m, x| m.max(x.abs())) + } + + /// Elastic Properties stretches the material the clip plays, by the requested ratio (#227). + #[test] + fn elastic_properties_stretches_the_clip_material() { + let (mut e, t, cid) = elastic_clip(20_000, 10_000, 20_000); + e.execute("clip.elastic_properties", &json!({"clips": [cid.0], "ratio": 2.0})).unwrap(); + assert_eq!(e.session().find_clip(cid).unwrap().1.length, 40_000); + assert!(rendered_peak(&e, t, cid) > 0.3, "the tone in the second half was lost"); + + let (mut e, t, cid) = elastic_clip(60_000, 20_000, 20_000); + e.execute("clip.elastic_properties", &json!({"clips": [cid.0], "ratio": 0.5})).unwrap(); + assert_eq!(rendered_peak(&e, t, cid), 0.0, "audio from past the clip end leaked in"); + + for (ratio, len) in [(4.0, 80_000), (0.2, 4_000)] { + let (mut e, _, cid) = elastic_clip(20_000, 10_000, 20_000); + e.execute("clip.elastic_properties", &json!({"clips": [cid.0], "ratio": ratio})).unwrap(); + assert_eq!(e.session().find_clip(cid).unwrap().1.length, len, "ratio {ratio}"); + } + } + #[test] fn remove_warp_keeps_the_audio_when_the_original_file_is_gone() { let mut e = crate::demo::demo_engine();