Audio processing functions have been added: normalize, apply_fade, an…

mistralrs-audio/src/lib.rs

@@ -101,6 +101,46 @@ impl AudioInput {
         }
         mono
     }
+
+    /// Normalize audio to prevent clipping
+    pub fn normalize(&mut self) -> &mut Self {
+        let max_amplitude = self.samples.iter().map(|s| s.abs()).fold(0.0f32, f32::max);
+        if max_amplitude > 0.0 && max_amplitude != 1.0 {
+            let scale = 1.0 / max_amplitude;
+            for sample in &mut self.samples {
+                *sample *= scale;
+            }
+        }
+        self
+    }
+
+    /// Apply fade in/out to reduce audio artifacts
+    pub fn apply_fade(&mut self, fade_in_samples: usize, fade_out_samples: usize) -> &mut Self {
+        let len = self.samples.len();
+        // Fade in
+        for i in 0..fade_in_samples.min(len) {
+            let factor = i as f32 / fade_in_samples as f32;
+            self.samples[i] *= factor;
+        }
+        // Fade out
+        for i in 0..fade_out_samples.min(len) {
+            let factor = (fade_out_samples - i) as f32 / fade_out_samples as f32;
+            self.samples[len - 1 - i] *= factor;
+        }
+        self
+    }
+
+    /// Remove DC offset (audio centered around 0)
+    pub fn remove_dc_offset(&mut self) -> &mut Self {
+        if self.samples.is_empty() {
+            return self;
+        }
+        let mean = self.samples.iter().sum::<f32>() / self.samples.len() as f32;
+        for sample in &mut self.samples {
+            *sample -= mean;
+        }
+        self
+    }
 }
 
 #[cfg(test)]
@@ -148,4 +188,44 @@ mod tests {
         assert_eq!(input.samples.len(), 80);
         assert_eq!(input.sample_rate, 8000);
     }
+
+    #[test]
+    fn test_normalize() {
+        let mut input = AudioInput {
+            samples: vec![0.2, -0.5, 0.8, -1.0],
+            sample_rate: 16000,
+            channels: 1,
+        };
+        input.normalize();
+        let max = input.samples.iter().map(|s| s.abs()).fold(0.0f32, f32::max);
+        assert!((max - 1.0).abs() < 1e-6);
+    }
+
+    #[test]
+    fn test_apply_fade() {
+        let mut input = AudioInput {
+            samples: vec![1.0; 10],
+            sample_rate: 16000,
+            channels: 1,
+        };
+        input.apply_fade(3, 3);
+        assert!((input.samples[0] - 0.0).abs() < 1e-6);
+        assert!(input.samples[1] > 0.0 && input.samples[1] < 1.0);
+        assert!(input.samples[2] > 0.0 && input.samples[2] < 1.0);
+        assert!(input.samples[3] == 1.0);
+        assert!((input.samples[9] - 0.0).abs() < 1e-6);
+    }
+
+    #[test]
+    fn test_remove_dc_offset() {
+        let mut input = AudioInput {
+            samples: vec![1.0, 1.0, 1.0, 1.0],
+            sample_rate: 16000,
+            channels: 1,
+        };
+        input.remove_dc_offset();
+        for s in input.samples {
+            assert!((s - 0.0).abs() < 1e-6);
+        }
+    }
 }