Add a fast-forward command

src/audio.rs

@@ -3,18 +3,20 @@ use std::time::Duration;
 use anyhow::{Result, bail};
 use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
 use itertools::Itertools;
-use rubato::{FftFixedInOut, Resampler};
+use rubato::{FastFixedOut, Resampler};
 use tracing::error;
 
 pub struct Audio {
     #[allow(unused)]
     stream: cpal::Stream,
-    sampler: FftFixedInOut<f32>,
+    sampler: FastFixedOut<f32>,
     input_buffer: Vec<Vec<f32>>,
     output_buffer: Vec<Vec<f32>>,
     sample_sink: rtrb::Producer<f32>,
 }
 
+const VB_FREQUENCY: usize = 41700;
+
 impl Audio {
     pub fn init() -> Result<Self> {
         let host = cpal::default_host();
@@ -28,7 +30,15 @@ impl Audio {
             bail!("No suitable output config available");
         };
         let mut config = config.with_max_sample_rate().config();
-        let sampler = FftFixedInOut::new(41700, config.sample_rate.0 as usize, 834, 2)?;
+        let resample_ratio = config.sample_rate.0 as f64 / VB_FREQUENCY as f64;
+        let chunk_size = (834.0 * resample_ratio) as usize;
+        let sampler = FastFixedOut::new(
+            resample_ratio,
+            64.0,
+            rubato::PolynomialDegree::Cubic,
+            chunk_size,
+            2,
+        )?;
         config.buffer_size = cpal::BufferSize::Fixed(sampler.output_frames_max() as u32);
 
         let input_buffer = sampler.input_buffer_allocate(true);
@@ -101,4 +111,10 @@ impl Audio {
             std::thread::sleep(Duration::from_micros(500));
         }
     }
+
+    pub fn set_speed(&mut self, speed: f64) -> Result<()> {
+        self.sampler
+            .set_resample_ratio_relative(1.0 / speed, false)?;
+        Ok(())
+    }
 }