test and fix take_duration fadeout

Author: dvdsk

CHANGELOG.md

@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Minimal builds without `cpal` audio output are now supported.
   See `README.md` for instructions. (#349)
 - Added `Sample::is_zero()` method for checking zero samples.
+- Added `TakeDuration::with_fadeout` similar to `TakeDuration::fadeout` but returns `Self`
 
 ### Changed
 - Breaking: `OutputStreamBuilder` should now be used to initialize an audio output stream.
@@ -34,6 +35,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Breaking: Sources wrapping an existing source had a public factory method
   which is now removed. Something like: `source::amplify(unamplified, 1.2)` must now be
   written as `unamplified.amplify(1.2)`.
+- Breaking: `TakeDuration::set_filter_fadeout()` has been removed. Use `TakeDuration.fadeout(true)`.
 - `SignalGenerator`'s `Function` is now Copy.
 
 

src/source/crossfade.rs

@@ -16,8 +16,7 @@ where
     I1: Source,
     I2: Source,
 {
-    let mut input_fadeout = input_fadeout.take_duration(duration);
-    input_fadeout.set_filter_fadeout();
+    let input_fadeout = input_fadeout.take_duration(duration).with_fadeout(true);
     let input_fadein = input_fadein.take_duration(duration).fade_in(duration);
     input_fadeout.mix(input_fadein)
 }

src/source/linear_ramp.rs

@@ -143,7 +143,7 @@ mod tests {
     use crate::Sample;
 
     /// Create a SamplesBuffer of identical samples with value `value`.
-    /// Returned buffer is one channel and has a sample rate of 1 hz.
+    /// Returned buffer is one channel and has a sample rate of 1 Hz.
     fn const_source(length: u8, value: Sample) -> SamplesBuffer {
         let data: Vec<f32> = (1..=length).map(|_| value).collect();
         SamplesBuffer::new(1, 1, data)

src/source/mix.rs

@@ -44,7 +44,7 @@ where
         let s1 = self.input1.next();
         let s2 = self.input2.next();
 
-        match (s1, s2) {
+        match dbg!((s1, s2)) {
             (Some(s1), Some(s2)) => Some(s1 + s2),
             (Some(s1), None) => Some(s1),
             (None, Some(s2)) => Some(s2),

src/source/take_duration.rs

@@ -64,10 +64,17 @@ where
         self.input
     }
 
+    /// Optionally the truncated source end with a FadeOut. The fade-out
+    /// covers the entire length of the take source.
+    pub fn fadeout(&mut self, enabled: bool) {
+        self.fadeout = enabled;
+    }
+
     /// Make the truncated source end with a FadeOut. The fade-out covers the
     /// entire length of the take source.
-    pub fn set_filter_fadeout(&mut self) {
-        self.fadeout = true;
+    pub fn with_fadeout(mut self, enabled: bool) -> Self {
+        self.fadeout = enabled;
+        self
     }
 
     /// Remove any filter set.
@@ -98,6 +105,14 @@ where
     type Item = <I as Iterator>::Item;
 
     // implementation is adapted of skip_duration
+    //
+    // if tuples are frames you could define fadeout as this:
+    //    [(1.0, 1.0), (1.0, 1.0), (1.0, 1.0)]
+    // -> [(1.0, 1.0), (0.5, 0.5), (0.0, 0.0)]
+    // instead because its simpler, faster and what previous rodio versions did we do:
+    //    [(1.0, 1.0), (1.0, 1.0), (1.0, 1.0)]
+    // -> [(1.0, .83), (.66, 0.5), (.33, .16)]
+    // at normal sample_rates you do not hear a difference
     fn next(&mut self) -> Option<<I as Iterator>::Item> {
         if self.input.parameters_changed() {
             self.remaining_ns -= self.duration_taken();
@@ -114,13 +129,15 @@ where
             return None;
         };
 
-        self.samples_taken += 1;
-        if self.fadeout {
+        let ret = if self.fadeout {
             let total = self.requested_duration.as_nanos() as u64;
-            Some(sample * self.remaining_ns as f32 / total as f32)
+            let remaining = self.remaining_ns - self.duration_taken();
+            Some(sample * remaining as f32 / total as f32)
         } else {
             Some(sample)
-        }
+        };
+        self.samples_taken += 1;
+        ret
     }
 }
 

tests/take_duration.rs

@@ -19,6 +19,9 @@ fn ends_on_frame_boundary(#[values(1.483, 2.999)] seconds_to_skip: f32) {
     let got = source
         .clone()
         .take_duration(Duration::from_secs_f32(seconds_to_skip))
+        // fadeout enables extra logic, run it too to check for bounds/overflow issues
+        .with_fadeout(true) 
+                            
         .count();
     assert!(got % source.channels() as usize == 0)
 }
@@ -49,6 +52,7 @@ fn param_changes_during_skip(#[values(6, 11)] seconds_to_skip: u64) {
     let took = source
         .clone()
         .take_duration(Duration::from_secs(seconds_to_skip))
+        .with_fadeout(true)
         .count();
 
     let spans = source.spans;
@@ -68,6 +72,33 @@ fn param_changes_during_skip(#[values(6, 11)] seconds_to_skip: u64) {
     );
 }
 
+#[test]
+fn fadeout() {
+    let span_duration = Duration::from_secs(5);
+    let source = TestSource::new()
+        .with_span(
+            TestSpan::ones()
+                .with_sample_rate(5)
+                .with_channel_count(1)
+                .with_exact_duration(span_duration),
+        )
+        .with_span(
+            TestSpan::ones()
+                .with_sample_rate(5)
+                .with_channel_count(2)
+                .with_exact_duration(span_duration),
+        );
+
+    let fade_out = source
+        .take_duration(span_duration.mul_f32(1.5))
+        .with_fadeout(true)
+        .collect::<Vec<_>>();
+    dbg!(&fade_out);
+    assert_eq!(fade_out.first(), Some(&1.0));
+    // fade_out ends the step before zero
+    assert!(fade_out.last().unwrap() > &0.0);
+}
+
 #[rstest]
 fn samples_taken(
     #[values(1, 2, 4)] channels: ChannelCount,
@@ -86,6 +117,7 @@ fn samples_taken(
 
     let samples = test_buffer
         .take_duration(Duration::from_secs(seconds_to_take as u64))
+        .with_fadeout(true)
         .count();
 
     let seconds_we_can_take = seconds_to_take.min(seconds);

tests/take_span.rs

@@ -7,13 +7,13 @@ mod test_support;
 fn param_changes_during_skip() {
     let source = TestSource::new()
         .with_span(
-            TestSpan::sample_indexes()
+            TestSpan::sample_counter()
                 .with_sample_rate(10)
                 .with_channel_count(1)
                 .with_sample_count(10),
         )
         .with_span(
-            TestSpan::sample_indexes()
+            TestSpan::sample_counter()
                 .with_sample_rate(20)
                 .with_channel_count(2)
                 .with_sample_count(10),

tests/test_support/mod.rs

@@ -18,6 +18,7 @@ pub enum SampleSource {
     Silence,
     List(Vec<f32>),
     SampleIndex,
+    Ones,
 }
 
 impl SampleSource {
@@ -29,6 +30,10 @@ impl SampleSource {
         channels: ChannelCount,
         numb_samples: usize,
     ) -> Option<Sample> {
+        if pos >= numb_samples {
+            return None;
+        }
+
         match self {
             SampleSource::SignalGen {
                 function,
@@ -41,12 +46,11 @@ impl SampleSource {
                     .collect();
                 samples.get(pos).copied()
             }
-            SampleSource::SampleIndex if pos < numb_samples => Some(pos_in_source as f32),
-            SampleSource::SampleIndex => None,
             SampleSource::SignalGen { samples, .. } => samples.get(pos).copied(),
-            SampleSource::Silence { .. } if pos < numb_samples => Some(0.0),
-            SampleSource::Silence { .. } => None,
             SampleSource::List(list) => list.get(pos).copied(),
+            SampleSource::SampleIndex => Some(pos_in_source as f32),
+            SampleSource::Silence { .. } => Some(0.0),
+            SampleSource::Ones => Some(1.0),
         }
     }
 }
@@ -74,7 +78,14 @@ impl TestSpan {
             channels: 1,
         }
     }
-    pub fn sample_indexes() -> TestSpanBuilder {
+    pub fn ones() -> TestSpanBuilder {
+        TestSpanBuilder {
+            sample_source: SampleSource::Ones,
+            sample_rate: 1,
+            channels: 1,
+        }
+    }
+    pub fn sample_counter() -> TestSpanBuilder {
         TestSpanBuilder {
             sample_source: SampleSource::SampleIndex,
             sample_rate: 1,