Feat/custom sample rate (#277)

maciejmakowski2003 · Maciej Makowski · web-flow · commit 472a535015d3 · 2025-01-30T19:17:29.000+01:00
* refactor: moved AudioPlayer to AudioContext

* refactor: refactored number of frames render by one call of renderAudio to RENDER_QUANTUM_SIZE

* fix: fixed bad access exception

* feat: added custom sample rate in audio context

* refactor: lateinit of AudioDecoder and sampleRate

---------

Co-authored-by: Maciej Makowski &lt;maciej.makowski2608@gmail.com&gt;
diff --git a/packages/react-native-audio-api/android/src/main/cpp/core/AudioPlayer.cpp b/packages/react-native-audio-api/android/src/main/cpp/core/AudioPlayer.cpp
@@ -21,13 +21,36 @@ AudioPlayer::AudioPlayer(
       ->setDataCallback(this)
       ->openStream(mStream_);
 
+  sampleRate_ = mStream_->getSampleRate();
   mBus_ = std::make_shared<AudioBus>(
-      getSampleRate(), RENDER_QUANTUM_SIZE, CHANNEL_COUNT);
+      sampleRate_, RENDER_QUANTUM_SIZE, CHANNEL_COUNT);
+  isInitialized_ = true;
+}
+
+AudioPlayer::AudioPlayer(
+    const std::function<void(AudioBus *, int)> &renderAudio,
+    int sampleRate)
+    : renderAudio_(renderAudio) {
+  AudioStreamBuilder builder;
+
+  builder.setSharingMode(SharingMode::Exclusive)
+      ->setFormat(AudioFormat::Float)
+      ->setFormatConversionAllowed(true)
+      ->setPerformanceMode(PerformanceMode::LowLatency)
+      ->setChannelCount(CHANNEL_COUNT)
+      ->setSampleRateConversionQuality(SampleRateConversionQuality::Medium)
+      ->setDataCallback(this)
+      ->setSampleRate(sampleRate)
+      ->openStream(mStream_);
+
+  sampleRate_ = sampleRate;
+  mBus_ = std::make_shared<AudioBus>(
+      sampleRate_, RENDER_QUANTUM_SIZE, CHANNEL_COUNT);
   isInitialized_ = true;
 }
 
 int AudioPlayer::getSampleRate() const {
-  return mStream_->getSampleRate();
+  return sampleRate_;
 }
 
 void AudioPlayer::start() {
diff --git a/packages/react-native-audio-api/android/src/main/cpp/core/AudioPlayer.h b/packages/react-native-audio-api/android/src/main/cpp/core/AudioPlayer.h
@@ -13,6 +13,9 @@ class AudioBus;
 class AudioPlayer : public AudioStreamDataCallback {
  public:
   explicit AudioPlayer(const std::function<void(AudioBus *, int)> &renderAudio);
+  AudioPlayer(
+      const std::function<void(AudioBus *, int)> &renderAudio,
+      int sampleRate);
 
   [[nodiscard]] int getSampleRate() const;
   void start();
@@ -28,6 +31,7 @@ class AudioPlayer : public AudioStreamDataCallback {
   std::shared_ptr<AudioStream> mStream_;
   std::shared_ptr<AudioBus> mBus_;
   bool isInitialized_ = false;
+  int sampleRate_;
 };
 
 } // namespace audioapi
diff --git a/packages/react-native-audio-api/common/cpp/HostObjects/AudioAPIInstallerHostObject.h b/packages/react-native-audio-api/common/cpp/HostObjects/AudioAPIInstallerHostObject.h
@@ -35,10 +35,18 @@ class AudioAPIInstallerHostObject
   }
 
   JSI_HOST_FUNCTION(createAudioContext) {
-    auto audioContext = std::make_shared<AudioContext>();
-    auto audioContextHostObject =
+      std::shared_ptr<AudioContext> audioContext;
+      if (args[0].isUndefined()) {
+          audioContext = std::make_shared<AudioContext>();
+      } else {
+          int sampleRate = static_cast<int>(args[0].getNumber());
+          audioContext = std::make_shared<AudioContext>(sampleRate);
+      }
+
+      auto audioContextHostObject =
         std::make_shared<AudioContextHostObject>(audioContext, promiseVendor_);
-    return jsi::Object::createFromHostObject(runtime, audioContextHostObject);
+
+      return jsi::Object::createFromHostObject(runtime, audioContextHostObject);
   }
 
  private:
diff --git a/packages/react-native-audio-api/common/cpp/core/AudioContext.cpp b/packages/react-native-audio-api/common/cpp/core/AudioContext.cpp
@@ -5,17 +5,31 @@
 #endif
 
 #include "AudioContext.h"
+#include "AudioDecoder.h"
 #include "AudioDestinationNode.h"
 
 namespace audioapi {
-
 AudioContext::AudioContext() : BaseAudioContext() {
 #ifdef ANDROID
   audioPlayer_ = std::make_shared<AudioPlayer>(this->renderAudio());
 #else
   audioPlayer_ = std::make_shared<IOSAudioPlayer>(this->renderAudio());
 #endif
   sampleRate_ = audioPlayer_->getSampleRate();
+  audioDecoder_ = std::make_shared<AudioDecoder>(sampleRate_);
+
+  audioPlayer_->start();
+}
+
+AudioContext::AudioContext(int sampleRate) : BaseAudioContext() {
+#ifdef ANDROID
+  audioPlayer_ = std::make_shared<AudioPlayer>(this->renderAudio(), sampleRate);
+#else
+  audioPlayer_ =
+      std::make_shared<IOSAudioPlayer>(this->renderAudio(), sampleRate);
+#endif
+  sampleRate_ = audioPlayer_->getSampleRate();
+  audioDecoder_ = std::make_shared<AudioDecoder>(sampleRate_);
 
   audioPlayer_->start();
 }
diff --git a/packages/react-native-audio-api/common/cpp/core/AudioContext.h b/packages/react-native-audio-api/common/cpp/core/AudioContext.h
@@ -14,6 +14,7 @@ class IOSAudioPlayer;
 class AudioContext : public BaseAudioContext {
  public:
   AudioContext();
+  explicit AudioContext(int sampleRate);
   ~AudioContext() override;
 
   void close();
diff --git a/packages/react-native-audio-api/common/cpp/core/BaseAudioContext.cpp b/packages/react-native-audio-api/common/cpp/core/BaseAudioContext.cpp
@@ -16,9 +16,7 @@
 
 namespace audioapi {
 
-BaseAudioContext::BaseAudioContext() : sampleRate_(DEFAULT_SAMPLE_RATE) {
-  audioDecoder_ = std::make_shared<AudioDecoder>(sampleRate_);
-
+BaseAudioContext::BaseAudioContext() {
   nodeManager_ = std::make_shared<AudioNodeManager>();
   destination_ = std::make_shared<AudioDestinationNode>(this);
 }
diff --git a/packages/react-native-audio-api/common/cpp/core/BaseAudioContext.h b/packages/react-native-audio-api/common/cpp/core/BaseAudioContext.h
@@ -58,9 +58,11 @@ class BaseAudioContext {
  protected:
   static std::string toString(ContextState state);
   std::shared_ptr<AudioDestinationNode> destination_;
-  std::shared_ptr<AudioDecoder> audioDecoder_;
+  // init in AudioContext or OfflineContext constructor
+  std::shared_ptr<AudioDecoder> audioDecoder_ {};
 
-  int sampleRate_;
+  // init in AudioContext or OfflineContext constructor
+  int sampleRate_ {};
   ContextState state_ = ContextState::RUNNING;
   std::shared_ptr<AudioNodeManager> nodeManager_;
 
diff --git a/packages/react-native-audio-api/ios/core/AudioPlayer.h b/packages/react-native-audio-api/ios/core/AudioPlayer.h
@@ -12,9 +12,12 @@ typedef void (^RenderAudioBlock)(AudioBufferList *outputBuffer, int numFrames);
 @property (nonatomic, strong) AVAudioFormat *format;
 @property (nonatomic, strong) AVAudioSourceNode *sourceNode;
 @property (nonatomic, copy) RenderAudioBlock renderAudio;
+@property (nonatomic, assign) int sampleRate;
 
 - (instancetype)initWithRenderAudioBlock:(RenderAudioBlock)renderAudio;
 
+- (instancetype)initWithRenderAudioBlock:(RenderAudioBlock)renderAudio sampleRate:(int)sampleRate;
+
 - (int)getSampleRate;
 
 - (void)start;
diff --git a/packages/react-native-audio-api/ios/core/AudioPlayer.m b/packages/react-native-audio-api/ios/core/AudioPlayer.m
@@ -28,7 +28,56 @@ - (instancetype)initWithRenderAudioBlock:(RenderAudioBlock)renderAudio
       @throw error;
     }
 
-    _format = [[AVAudioFormat alloc] initStandardFormatWithSampleRate:[self.audioSession sampleRate] channels:2];
+    self.sampleRate = [self.audioSession sampleRate];
+
+    _format = [[AVAudioFormat alloc] initStandardFormatWithSampleRate:self.sampleRate channels:2];
+
+    __weak typeof(self) weakSelf = self;
+    _sourceNode = [[AVAudioSourceNode alloc] initWithFormat:self.format
+                                                renderBlock:^OSStatus(
+                                                    BOOL *isSilence,
+                                                    const AudioTimeStamp *timestamp,
+                                                    AVAudioFrameCount frameCount,
+                                                    AudioBufferList *outputData) {
+                                                  return [weakSelf renderCallbackWithIsSilence:isSilence
+                                                                                     timestamp:timestamp
+                                                                                    frameCount:frameCount
+                                                                                    outputData:outputData];
+                                                }];
+  }
+
+  return self;
+}
+
+- (instancetype)initWithRenderAudioBlock:(RenderAudioBlock)renderAudio sampleRate:(int)sampleRate
+{
+  if (self = [super init]) {
+    self.renderAudio = [renderAudio copy];
+    self.audioEngine = [[AVAudioEngine alloc] init];
+    self.audioEngine.mainMixerNode.outputVolume = 1;
+
+    self.audioSession = AVAudioSession.sharedInstance;
+    NSError *error = nil;
+
+    // TODO:
+    // We will probably want to change it to AVAudioSessionCategoryPlayAndRecord in the future.
+    // Eventually we to make this a dynamic setting, if user of the lib wants to use recording features.
+    // But setting a recording category might require some setup first, so lets skip it for now :)
+    [self.audioSession setCategory:AVAudioSessionCategoryPlayback error:&error];
+
+    if (error != nil) {
+      @throw error;
+    }
+
+    [self.audioSession setActive:true error:&error];
+
+    if (error != nil) {
+      @throw error;
+    }
+
+    self.sampleRate = sampleRate;
+
+    _format = [[AVAudioFormat alloc] initStandardFormatWithSampleRate:self.sampleRate channels:2];
 
     __weak typeof(self) weakSelf = self;
     _sourceNode = [[AVAudioSourceNode alloc] initWithFormat:self.format
@@ -49,7 +98,7 @@ - (instancetype)initWithRenderAudioBlock:(RenderAudioBlock)renderAudio
 
 - (int)getSampleRate
 {
-  return [self.audioSession sampleRate];
+  return self.sampleRate;
 }
 
 - (void)start
diff --git a/packages/react-native-audio-api/ios/core/IOSAudioPlayer.h b/packages/react-native-audio-api/ios/core/IOSAudioPlayer.h
@@ -22,6 +22,9 @@ class IOSAudioPlayer {
  public:
   explicit IOSAudioPlayer(
       const std::function<void(AudioBus *, int)> &renderAudio);
+  IOSAudioPlayer(
+      const std::function<void(AudioBus *, int)> &renderAudio,
+      int sampleRate);
   ~IOSAudioPlayer();
 
   int getSampleRate() const;
diff --git a/packages/react-native-audio-api/ios/core/IOSAudioPlayer.mm b/packages/react-native-audio-api/ios/core/IOSAudioPlayer.mm
@@ -34,6 +34,35 @@
   };
 
   audioPlayer_ = [[AudioPlayer alloc] initWithRenderAudioBlock:renderAudioBlock];
+  audioBus_ = new AudioBus([audioPlayer_ getSampleRate], RENDER_QUANTUM_SIZE, CHANNEL_COUNT);
+}
+
+IOSAudioPlayer::IOSAudioPlayer(const std::function<void(AudioBus *, int)> &renderAudio, int sampleRate)
+    : renderAudio_(renderAudio), audioBus_(0)
+{
+  RenderAudioBlock renderAudioBlock = ^(AudioBufferList *outputData, int numFrames) {
+    int processedFrames = 0;
+
+    while (processedFrames < numFrames) {
+      int framesToProcess = std::min(numFrames - processedFrames, RENDER_QUANTUM_SIZE);
+      renderAudio_(audioBus_, framesToProcess);
+
+      // TODO: optimize this with SIMD?
+      for (int channel = 0; channel < CHANNEL_COUNT; channel += 1) {
+        float *outputChannel = (float *)outputData->mBuffers[channel].mData;
+        auto *inputChannel = audioBus_->getChannel(channel)->getData();
+
+        for (int i = 0; i < framesToProcess; i++) {
+          outputChannel[processedFrames + i] = inputChannel[i];
+        }
+      }
+
+      processedFrames += framesToProcess;
+    }
+  };
+
+  audioPlayer_ = [[AudioPlayer alloc] initWithRenderAudioBlock:renderAudioBlock sampleRate:sampleRate];
+  audioBus_ = new AudioBus([audioPlayer_ getSampleRate], RENDER_QUANTUM_SIZE, CHANNEL_COUNT);
 }
 
 IOSAudioPlayer::~IOSAudioPlayer()
diff --git a/packages/react-native-audio-api/src/core/AudioContext.ts b/packages/react-native-audio-api/src/core/AudioContext.ts
@@ -2,8 +2,8 @@ import { IAudioContext } from '../interfaces';
 import BaseAudioContext from './BaseAudioContext';
 
 export default class AudioContext extends BaseAudioContext {
-  constructor() {
-    super(global.__AudioAPIInstaller.createAudioContext());
+  constructor(sampleRate?: number) {
+    super(global.__AudioAPIInstaller.createAudioContext(sampleRate));
   }
 
   close(): void {
diff --git a/packages/react-native-audio-api/src/index.ts b/packages/react-native-audio-api/src/index.ts
@@ -420,7 +420,7 @@ export class AudioContext {
   readonly destination: AudioDestinationNode;
   readonly sampleRate: number;
 
-  constructor() {
+  constructor(_sampleRate?: number) {
     this.context = new window.AudioContext();
 
     this.sampleRate = this.context.sampleRate;
diff --git a/packages/react-native-audio-api/src/specs/global.d.ts b/packages/react-native-audio-api/src/specs/global.d.ts
@@ -2,7 +2,7 @@
 import type { IAudioContext } from '../interfaces';
 
 type AudioAPIInstaller = {
-  createAudioContext: () => IAudioContext;
+  createAudioContext: (sampleRate?: number) => IAudioContext;
 };
 
 declare global {

Original file line number	Diff line number	Diff line change
`@@ -16,9 +16,7 @@`
`16`	`16`
`17`	`17`	`namespace audioapi {`
`18`	`18`
`19`		`-BaseAudioContext::BaseAudioContext() : sampleRate_(DEFAULT_SAMPLE_RATE) {`
`20`		`- audioDecoder_ = std::make_shared<AudioDecoder>(sampleRate_);`
`21`		`-`
	`19`	`+BaseAudioContext::BaseAudioContext() {`
`22`	`20`	`nodeManager_ = std::make_shared<AudioNodeManager>();`
`23`	`21`	`destination_ = std::make_shared<AudioDestinationNode>(this);`
`24`	`22`	`}`