From dee0e194669a6afafe4b1a0d7e3a6b8018922efa Mon Sep 17 00:00:00 2001
From: Yesterday17 <mmf@mmf.moe>
Date: Sun, 22 Sep 2024 18:42:56 +0800
Subject: [PATCH] feat(playback): allow to specify sample rate and skip useless
 resample

---
 anni-playback/examples/gapless.rs    |  2 +-
 anni-playback/examples/player.rs     |  2 +-
 anni-playback/examples/tui.rs        |  2 +-
 anni-playback/src/cpal_output.rs     | 19 ++++++++++++-------
 anni-playback/src/decoder/decoder.rs |  5 ++---
 anni-playback/src/player.rs          | 14 ++++++++++++--
 6 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/anni-playback/examples/gapless.rs b/anni-playback/examples/gapless.rs
index 9608eb3..0af1c62 100644
--- a/anni-playback/examples/gapless.rs
+++ b/anni-playback/examples/gapless.rs
@@ -15,7 +15,7 @@ impl Player {
         thread::spawn({
             let controls = controls.clone();
             move || {
-                let decoder = Decoder::new(controls, thread_killer.1.clone());
+                let decoder = Decoder::new(controls, 48000, thread_killer.1.clone());
                 decoder.start();
             }
         });
diff --git a/anni-playback/examples/player.rs b/anni-playback/examples/player.rs
index b7264ce..01e85b3 100644
--- a/anni-playback/examples/player.rs
+++ b/anni-playback/examples/player.rs
@@ -15,7 +15,7 @@ impl Player {
         thread::spawn({
             let controls = controls.clone();
             move || {
-                let decoder = Decoder::new(controls, thread_killer.1.clone());
+                let decoder = Decoder::new(controls, 48000, thread_killer.1.clone());
                 decoder.start();
             }
         });
diff --git a/anni-playback/examples/tui.rs b/anni-playback/examples/tui.rs
index 9de900d..b27c4e6 100644
--- a/anni-playback/examples/tui.rs
+++ b/anni-playback/examples/tui.rs
@@ -27,7 +27,7 @@ impl Player {
         thread::spawn({
             let controls = controls.clone();
             move || {
-                let decoder = Decoder::new(controls, thread_killer.1.clone());
+                let decoder = Decoder::new(controls, 48000, thread_killer.1.clone());
                 decoder.start();
             }
         });
diff --git a/anni-playback/src/cpal_output.rs b/anni-playback/src/cpal_output.rs
index 3159b13..951b932 100644
--- a/anni-playback/src/cpal_output.rs
+++ b/anni-playback/src/cpal_output.rs
@@ -256,13 +256,18 @@ impl CpalOutput {
             return;
         }
 
-        let mut samples = if let Some(resampler) = &mut self.resampler {
-            // If there is a resampler, then write resampled values
-            // instead of the normal `samples`.
-            resampler.resample(decoded).unwrap_or(&[])
-        } else {
-            self.sample_buffer.copy_interleaved_ref(decoded);
-            self.sample_buffer.samples()
+        let need_resample = decoded.spec().rate != self.spec.rate;
+        let mut samples = match (need_resample, &mut self.resampler) {
+            (true, Some(resampler)) => {
+                // If there is a resampler, then write resampled values
+                // instead of the normal `samples`.
+                resampler.resample(decoded).unwrap_or(&[])
+            }
+            _ => {
+                // no resampler, or the target sampe rate is the same as the input
+                self.sample_buffer.copy_interleaved_ref(decoded);
+                self.sample_buffer.samples()
+            }
         };
 
         if self.controls.is_normalizing() {
diff --git a/anni-playback/src/decoder/decoder.rs b/anni-playback/src/decoder/decoder.rs
index a622952..df421dd 100644
--- a/anni-playback/src/decoder/decoder.rs
+++ b/anni-playback/src/decoder/decoder.rs
@@ -75,9 +75,8 @@ pub struct Decoder {
 
 impl Decoder {
     /// Creates a new decoder.
-    pub fn new(controls: Controls, thread_killer: Receiver<bool>) -> Self {
-        // TODO: allow specifying sample rate by user
-        let spec = SignalSpec::new_with_layout(44100, Layout::Stereo);
+    pub fn new(controls: Controls, sample_rate: u32, thread_killer: Receiver<bool>) -> Self {
+        let spec = SignalSpec::new_with_layout(sample_rate, Layout::Stereo);
 
         Decoder {
             thread_killer,
diff --git a/anni-playback/src/player.rs b/anni-playback/src/player.rs
index df27bcf..6cfe253 100644
--- a/anni-playback/src/player.rs
+++ b/anni-playback/src/player.rs
@@ -33,11 +33,21 @@ pub struct AnniPlayer {
     cache_store: CacheStore, // root of cache
 }
 
+pub struct AnniPlayerOptions {
+    pub sample_rate: u32,
+    pub cache_path: PathBuf,
+}
+
 impl AnniPlayer {
     pub fn new(
         provider: TypedPriorityProvider<ProviderProxy>,
-        cache_path: PathBuf,
+        options: AnniPlayerOptions,
     ) -> (Self, Receiver<PlayerEvent>) {
+        let AnniPlayerOptions {
+            sample_rate,
+            cache_path,
+        } = options;
+
         let (controls, receiver, killer) = {
             let (sender, receiver) = mpsc::channel();
             let controls = Controls::new(sender);
@@ -48,7 +58,7 @@ impl AnniPlayer {
                 .spawn({
                     let controls = controls.clone();
                     move || {
-                        let decoder = Decoder::new(controls, thread_killer.1);
+                        let decoder = Decoder::new(controls, sample_rate, thread_killer.1);
 
                         decoder.start();
                     }