Renamed this field for consistency

with other library structs.

src/source/fadein.rs

@@ -11,14 +11,14 @@ where
     I::Item: Sample,
 {
     FadeIn {
-        ramp: linear_gain_ramp(input, duration, 0.0f32, 1.0f32, false),
+        input: linear_gain_ramp(input, duration, 0.0f32, 1.0f32, false),
     }
 }
 
 /// Filter that modifies raises the volume from silence over a time period.
 #[derive(Clone, Debug)]
 pub struct FadeIn<I> {
-    ramp: LinearGainRamp<I>
+    input: LinearGainRamp<I>
 }
 
 impl<I> FadeIn<I>
@@ -29,19 +29,19 @@ where
     /// Returns a reference to the inner source.
     #[inline]
     pub fn inner(&self) -> &I {
-        self.ramp.inner()
+        self.input.inner()
     }
 
     /// Returns a mutable reference to the inner source.
     #[inline]
     pub fn inner_mut(&mut self) -> &mut I {
-        self.ramp.inner_mut()
+        self.input.inner_mut()
     }
 
     /// Returns the inner source.
     #[inline]
     pub fn into_inner(self) -> I {
-        self.ramp.into_inner()
+        self.input.into_inner()
     }
 }
 

src/source/linear_ramp.rs

@@ -25,6 +25,7 @@ where
         start_gain,
         end_gain,
         clamp_end,
+        sample_idx: 0u64,
     }
 }
 
@@ -37,6 +38,7 @@ pub struct LinearGainRamp<I> {
     start_gain: f32,
     end_gain: f32,
     clamp_end: bool,
+    sample_idx: u64
 }
 
 impl<I> LinearGainRamp<I>
@@ -82,6 +84,8 @@ where
                 factor = 1.0f32;
             }
         } else {
+            self.sample_idx += 1;
+
             factor = f32::lerp(
                 self.start_gain,
                 self.end_gain,
@@ -90,8 +94,11 @@ where
             );
         }
 
-        self.elapsed_ns +=
-            1000000000.0 / (self.input.sample_rate() as f32 * self.channels() as f32);
+        if self.sample_idx % (self.channels() as u64) == 0 {
+            self.elapsed_ns +=
+                1000000000.0 / (self.input.sample_rate() as f32);
+        }
+
 
         self.input.next().map(|value| value.amplify(factor))
     }