Fix pitch correction latency

apps/common-app/src/examples/AudioVisualizer/AudioVisualizer.tsx

@@ -131,16 +131,14 @@ const AudioVisualizer: React.FC = () => {
         }
       />
       <View
-        style={{ flex: 0.5, justifyContent: 'center', alignItems: 'center' }}
-      >
+        style={{ flex: 0.5, justifyContent: 'center', alignItems: 'center' }}>
         {isLoading && <ActivityIndicator color="#FFFFFF" />}
         <View
           style={{
             justifyContent: 'center',
             flexDirection: 'row',
             marginTop: layout.spacing * 2,
-          }}
-        >
+          }}>
           <Button
             onPress={handlePlayPause}
             title={isPlaying ? 'Pause' : 'Play'}

packages/audiodocs/docs/sources/audio-buffer-base-source-node.mdx

@@ -23,9 +23,32 @@ It inherits all properties from [`AudioScheduledSourceNode`](/docs/sources/audio
 
 ## Methods
 
-`AudioBufferBaseSourceNode` does not define any additional methods.
 It inherits all methods from [`AudioScheduledSourceNode`](/docs/sources/audio-scheduled-source-node#methods).
 
+### `getLatency`
+
+Returns the playback latency introduced by the pitch correction algorithm, in seconds.
+When scheduling precise playback times, start input samples this many seconds earlier to compensate for processing delay.
+Typically around `0.06s` when pitch correction is enabled, and `0` otherwise.
+
+#### Returns `number`.
+
+<details>
+<summary>Example usage</summary>
+```tsx
+const source = audioContext.createBufferSource({ pitchCorrection: true });
+source.buffer = buffer;
+source.connect(audioContext.destination);
+
+const latency = source.getLatency();
+
+// Schedule playback slightly earlier to compensate for latency
+const startTime = audioContext.currentTime + 1.0; // play in 1 second
+source.start(startTime - latency);
+```
+</details>
+
+
 ## Events
 
 ### `onPositionChanged` <MobileOnly />

packages/audiodocs/docs/sources/audio-buffer-queue-source-node.mdx

@@ -22,6 +22,12 @@ interface AudioBufferBaseSourceNodeOptions {
 }
 ```
 
+:::caution
+The pitch correction algorithm introduces processing latency.
+As a result, when scheduling precise playback times, you should start input samples slightly ahead of the intended playback time.
+For more details, see [getLatency()](/docs/sources/audio-buffer-base-source-node#getlatency).
+:::
+
 ## Example
 
 ```tsx
@@ -39,8 +45,8 @@ function App() {
     const audioBufferQueue = audioContextRef.current.createBufferQueueSource();
     const buffer1 = ...; // Load your audio buffer here
     const buffer2 = ...; // Load another audio buffer if needed
-    audioBufferQueue.enqueueBuffer(buffer1, false);
-    audioBufferQueue.enqueueBuffer(buffer2, true); // Last buffer should be marked as is
+    audioBufferQueue.enqueueBuffer(buffer1);
+    audioBufferQueue.enqueueBuffer(buffer2);
     audioBufferQueue.connect(audioContextRef.current.destination);
     audioBufferQueue.start(audioContextRef.current.currentTime);
 }

packages/audiodocs/docs/sources/audio-buffer-source-node.mdx

@@ -12,7 +12,6 @@ import { useGainAdsrPlayground } from '@site/src/components/InteractivePlaygroun
 
 # AudioBufferSourceNode
 
-The `AudioBufferSourceNode` is an [`AudioBufferBaseSourceNode`](/docs/sources/audio-buffer-base-source-node) which represents audio source with in-memory audio data, stored in
 The `AudioBufferSourceNode` is an [`AudioBufferBaseSourceNode`](/docs/sources/audio-buffer-base-source-node) which represents audio source with in-memory audio data, stored in
 [`AudioBuffer`](/docs/sources/audio-buffer). You can use it for audio playback, including standard pause and resume functionalities.
 
@@ -40,6 +39,14 @@ interface AudioBufferBaseSourceNodeOptions {
 }
 ```
 
+:::caution
+The pitch correction algorithm introduces processing latency.
+As a result, when scheduling precise playback times, you should start input samples slightly ahead of the intended playback time.
+For more details, see [getLatency()](/docs/sources/audio-buffer-base-source-node#getlatency).
+
+If you plan to play multiple buffers one after another, consider using [AudioBufferQueueSourceNode](/docs/sources/audio-buffer-queue-source-node)
+:::
+
 ## Example
 
 ```tsx
@@ -100,6 +107,7 @@ Schedules the `AudioBufferSourceNode` to start playback of audio data contained
 
 #### Returns `undefined`.
 
+
 ## Events
 
 ### `onLoopEnded`

packages/react-native-audio-api/common/cpp/audioapi/HostObjects/sources/AudioBufferBaseSourceNodeHostObject.cpp

@@ -20,6 +20,11 @@ AudioBufferBaseSourceNodeHostObject::AudioBufferBaseSourceNodeHostObject(
           AudioBufferBaseSourceNodeHostObject, onPositionChanged),
       JSI_EXPORT_PROPERTY_SETTER(
           AudioBufferBaseSourceNodeHostObject, onPositionChangedInterval));
+
+  addFunctions(
+      JSI_EXPORT_FUNCTION(AudioBufferBaseSourceNodeHostObject, getInputLatency),
+      JSI_EXPORT_FUNCTION(
+          AudioBufferBaseSourceNodeHostObject, getOutputLatency));
 }
 
 AudioBufferBaseSourceNodeHostObject::~AudioBufferBaseSourceNodeHostObject() {
@@ -70,4 +75,18 @@ JSI_PROPERTY_SETTER_IMPL(
   sourceNode->setOnPositionChangedInterval(static_cast<int>(value.getNumber()));
 }
 
+JSI_HOST_FUNCTION_IMPL(AudioBufferBaseSourceNodeHostObject, getInputLatency) {
+  auto audioBufferBaseSourceNode =
+      std::static_pointer_cast<AudioBufferBaseSourceNode>(node_);
+
+  return audioBufferBaseSourceNode->getInputLatency();
+}
+
+JSI_HOST_FUNCTION_IMPL(AudioBufferBaseSourceNodeHostObject, getOutputLatency) {
+  auto audioBufferBaseSourceNode =
+      std::static_pointer_cast<AudioBufferBaseSourceNode>(node_);
+
+  return audioBufferBaseSourceNode->getOutputLatency();
+}
+
 } // namespace audioapi

packages/react-native-audio-api/common/cpp/audioapi/HostObjects/sources/AudioBufferBaseSourceNodeHostObject.h

@@ -24,6 +24,9 @@ class AudioBufferBaseSourceNodeHostObject
 
     JSI_PROPERTY_SETTER_DECL(onPositionChanged);
     JSI_PROPERTY_SETTER_DECL(onPositionChangedInterval);
+
+    JSI_HOST_FUNCTION_DECL(getInputLatency);
+    JSI_HOST_FUNCTION_DECL(getOutputLatency);
 };
 
 } // namespace audioapi

packages/react-native-audio-api/common/cpp/audioapi/core/sources/AudioBufferBaseSourceNode.cpp

@@ -60,6 +60,22 @@ std::mutex &AudioBufferBaseSourceNode::getBufferLock() {
   return bufferLock_;
 }
 
+double AudioBufferBaseSourceNode::getInputLatency() const {
+  if (pitchCorrection_) {
+    return static_cast<double>(stretch_->inputLatency()) /
+        context_->getSampleRate();
+  }
+  return 0;
+}
+
+double AudioBufferBaseSourceNode::getOutputLatency() const {
+  if (pitchCorrection_) {
+    return static_cast<double>(stretch_->outputLatency()) /
+        context_->getSampleRate();
+  }
+  return 0;
+}
+
 void AudioBufferBaseSourceNode::sendOnPositionChangedEvent() {
   auto onPositionChangedCallbackId =
       onPositionChangedCallbackId_.load(std::memory_order_acquire);

packages/react-native-audio-api/common/cpp/audioapi/core/sources/AudioBufferBaseSourceNode.h

@@ -22,6 +22,8 @@ class AudioBufferBaseSourceNode : public AudioScheduledSourceNode {
   void setOnPositionChangedCallbackId(uint64_t callbackId);
   void setOnPositionChangedInterval(int interval);
   [[nodiscard]] int getOnPositionChangedInterval() const;
+  [[nodiscard]] double getInputLatency() const;
+  [[nodiscard]] double getOutputLatency() const;
 
  protected:
     // pitch correction

packages/react-native-audio-api/common/cpp/audioapi/core/sources/AudioBufferQueueSourceNode.cpp

@@ -17,6 +17,19 @@ AudioBufferQueueSourceNode::AudioBufferQueueSourceNode(
   buffers_ = {};
   stretch_->presetDefault(channelCount_, context_->getSampleRate());
 
+  if (pitchCorrection) {
+    // If pitch correction is enabled, add extra frames at the end
+    // to compensate for processing latency.
+    addExtraTailFrames_ = true;
+
+    int extraTailFrames =
+        static_cast<int>(stretch_->inputLatency() + stretch_->outputLatency());
+    tailBuffer_ = std::make_shared<AudioBuffer>(
+        channelCount_, extraTailFrames, context_->getSampleRate());
+
+    tailBuffer_->bus_->zero();
+  }
+
   isInitialized_ = true;
 }
 
@@ -169,10 +182,17 @@ void AudioBufferQueueSourceNode::processWithoutInterpolation(
           "ended", onEndedCallbackId_, body);
 
       if (buffers_.empty()) {
-        processingBus->zero(writeIndex, framesLeft);
-        readIndex = 0;
+        if (addExtraTailFrames_) {
+          buffers_.emplace(bufferId_, tailBuffer_);
+          bufferId_++;
 
-        break;
+          addExtraTailFrames_ = false;
+        } else if (buffers_.empty()) {
+          processingBus->zero(writeIndex, framesLeft);
+          readIndex = 0;
+
+          break;
+        }
       }
 
       data = buffers_.front();

packages/react-native-audio-api/common/cpp/audioapi/core/sources/AudioBufferQueueSourceNode.h

@@ -39,6 +39,8 @@ class AudioBufferQueueSourceNode : public AudioBufferBaseSourceNode {
     size_t bufferId_ = 0;
 
     bool isPaused_ = false;
+    bool addExtraTailFrames_ = false;
+    std::shared_ptr<AudioBuffer> tailBuffer_;
 
     double playedBuffersDuration_ = 0;
 

packages/react-native-audio-api/common/cpp/audioapi/core/sources/AudioBufferSourceNode.cpp

@@ -82,17 +82,30 @@ void AudioBufferSourceNode::setBuffer(
   }
 
   buffer_ = buffer;
-  alignedBus_ = std::make_shared<AudioBus>(*buffer_->bus_);
   channelCount_ = buffer_->getNumberOfChannels();
 
+  stretch_->presetDefault(channelCount_, buffer_->getSampleRate());
+
+  if (pitchCorrection_) {
+    int extraTailFrames = static_cast<int>(
+        (getInputLatency() + getOutputLatency()) * context_->getSampleRate());
+    size_t totalSize = buffer_->getLength() + extraTailFrames;
+
+    alignedBus_ = std::make_shared<AudioBus>(
+        totalSize, channelCount_, buffer_->getSampleRate());
+    alignedBus_->copy(buffer_->bus_.get(), 0, 0, buffer_->getLength());
+
+    alignedBus_->zero(buffer_->getLength(), extraTailFrames);
+  } else {
+    alignedBus_ = std::make_shared<AudioBus>(*buffer_->bus_);
+  }
+
   audioBus_ = std::make_shared<AudioBus>(
       RENDER_QUANTUM_SIZE, channelCount_, context_->getSampleRate());
   playbackRateBus_ = std::make_shared<AudioBus>(
       RENDER_QUANTUM_SIZE * 3, channelCount_, context_->getSampleRate());
 
   loopEnd_ = buffer_->getDuration();
-
-  stretch_->presetDefault(channelCount_, buffer_->getSampleRate());
 }
 
 void AudioBufferSourceNode::start(double when, double offset, double duration) {

packages/react-native-audio-api/common/cpp/audioapi/core/sources/AudioBufferSourceNode.h

@@ -4,9 +4,9 @@
 #include <audioapi/core/sources/AudioBufferBaseSourceNode.h>
 #include <audioapi/libs/signalsmith-stretch/signalsmith-stretch.h>
 
-#include <memory>
-#include <cstddef>
 #include <algorithm>
+#include <cstddef>
+#include <memory>
 #include <string>
 
 namespace audioapi {
@@ -37,7 +37,7 @@ class AudioBufferSourceNode : public AudioBufferBaseSourceNode {
   void setOnLoopEndedCallbackId(uint64_t callbackId);
 
  protected:
-  std::shared_ptr<AudioBus> processNode(const std::shared_ptr<AudioBus>& processingBus, int framesToProcess) override;
+  std::shared_ptr<AudioBus> processNode(const std::shared_ptr<AudioBus> &processingBus, int framesToProcess) override;
   double getCurrentPosition() const override;
 
  private:
@@ -55,13 +55,13 @@ class AudioBufferSourceNode : public AudioBufferBaseSourceNode {
   void sendOnLoopEndedEvent();
 
   void processWithoutInterpolation(
-      const std::shared_ptr<AudioBus>& processingBus,
+      const std::shared_ptr<AudioBus> &processingBus,
       size_t startOffset,
       size_t offsetLength,
       float playbackRate) override;
 
   void processWithInterpolation(
-      const std::shared_ptr<AudioBus>& processingBus,
+      const std::shared_ptr<AudioBus> &processingBus,
       size_t startOffset,
       size_t offsetLength,
       float playbackRate) override;

packages/react-native-audio-api/src/core/AudioBufferBaseSourceNode.ts

@@ -51,4 +51,12 @@ export default class AudioBufferBaseSourceNode extends AudioScheduledSourceNode
   public set onPositionChangedInterval(value: number) {
     (this.node as IAudioBufferBaseSourceNode).onPositionChangedInterval = value;
   }
+
+  public getLatency(): number {
+    return (
+      (this.node as IAudioBufferBaseSourceNode).getOutputLatency() +
+      (this.node as IAudioBufferBaseSourceNode).getInputLatency() *
+        (this.node as IAudioBufferBaseSourceNode).playbackRate.value
+    );
+  }
 }

packages/react-native-audio-api/src/interfaces.ts

@@ -144,6 +144,9 @@ export interface IAudioBufferBaseSourceNode extends IAudioScheduledSourceNode {
   detune: IAudioParam;
   playbackRate: IAudioParam;
 
+  getInputLatency: () => number;
+  getOutputLatency: () => number;
+
   // passing subscriptionId(uint_64 in cpp, string in js) to the cpp
   onPositionChanged: string;
   // set how often the onPositionChanged event is called