fix: base audio context construction + audio player start stop events (#215)

Author: michalsek

apps/common-app/src/examples/DrumMachine/usePlayer.tsx

@@ -133,6 +133,10 @@ export default function usePlayer(options: PlayerOptions) {
       playingInstruments.value = getPlayingInstruments();
     }
 
+    return () => {
+      audioContext.close();
+    };
+
     // \/ Shared values are not necessary in deps array
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [isPlaying, setup]);

packages/react-native-audio-api/android/src/main/cpp/AudioPlayer/AudioPlayer.cpp

@@ -21,6 +21,7 @@ AudioPlayer::AudioPlayer(const std::function<void(AudioBus*, int)> &renderAudio)
       ->openStream(mStream_);
 
   mBus_ = std::make_shared<AudioBus>(getSampleRate(), getBufferSizeInFrames(), CHANNEL_COUNT);
+  isInitialized_ = true;
 }
 
 int AudioPlayer::getSampleRate() const {
@@ -38,6 +39,8 @@ void AudioPlayer::start() {
 }
 
 void AudioPlayer::stop() {
+  isInitialized_ = false;
+
   if (mStream_) {
     mStream_->requestStop();
     mStream_->close();
@@ -49,8 +52,11 @@ DataCallbackResult AudioPlayer::onAudioReady(
     AudioStream *oboeStream,
     void *audioData,
     int32_t numFrames) {
-  auto buffer = static_cast<float *>(audioData);
+  if (!isInitialized_) {
+    return DataCallbackResult::Continue;
+  }
 
+  auto buffer = static_cast<float *>(audioData);
   renderAudio_(mBus_.get(), numFrames);
 
   // TODO: optimize this with SIMD?

packages/react-native-audio-api/android/src/main/cpp/AudioPlayer/AudioPlayer.h

@@ -28,6 +28,7 @@ class AudioPlayer : public AudioStreamDataCallback {
   std::function<void(AudioBus*, int)> renderAudio_;
   std::shared_ptr<AudioStream> mStream_;
   std::shared_ptr<AudioBus> mBus_;
+  bool isInitialized_ = false;
 };
 
 } // namespace audioapi

packages/react-native-audio-api/common/cpp/core/AudioContext.cpp

@@ -9,16 +9,13 @@
 
 namespace audioapi {
 
-AudioContext::AudioContext() : BaseAudioContext() {}
+AudioContext::AudioContext() : BaseAudioContext() {
+  audioPlayer_->start();
+}
 
 void AudioContext::close() {
   state_ = ContextState::CLOSED;
-
-  if (audioPlayer_) {
-    audioPlayer_->stop();
-  }
-
-  audioPlayer_.reset();
-  destination_.reset();
+  audioPlayer_->stop();
 }
+
 } // namespace audioapi

packages/react-native-audio-api/common/cpp/core/AudioDestinationNode.cpp

@@ -24,13 +24,13 @@ double AudioDestinationNode::getCurrentTime() const {
 }
 
 void AudioDestinationNode::renderAudio(AudioBus *destinationBus, int32_t numFrames) {
-  context_->getNodeManager()->preProcessGraph();
-  destinationBus->zero();
-
-  if (!numFrames) {
+  if (!numFrames || !destinationBus || !isInitialized_) {
     return;
   }
 
+  context_->getNodeManager()->preProcessGraph();
+  destinationBus->zero();
+
   AudioBus* processedBus = processAudio(destinationBus, numFrames);
 
   if (processedBus && processedBus != destinationBus) {

packages/react-native-audio-api/common/cpp/core/BaseAudioContext.cpp

@@ -30,11 +30,19 @@ BaseAudioContext::BaseAudioContext() {
   sampleRate_ = audioPlayer_->getSampleRate();
   bufferSizeInFrames_ = audioPlayer_->getBufferSizeInFrames();
 
-  audioPlayer_->start();
   nodeManager_ = std::make_shared<AudioNodeManager>();
   destination_ = std::make_shared<AudioDestinationNode>(this);
 }
 
+BaseAudioContext::~BaseAudioContext() {
+  if (isRunning()) {
+    return;
+  }
+
+  state_ = ContextState::CLOSED;
+  audioPlayer_->stop();
+}
+
 std::string BaseAudioContext::getState() {
   return BaseAudioContext::toString(state_);
 }
@@ -96,7 +104,7 @@ std::shared_ptr<PeriodicWave> BaseAudioContext::createPeriodicWave(
 }
 
 std::function<void(AudioBus *, int)> BaseAudioContext::renderAudio() {
-  if (state_ == ContextState::CLOSED) {
+  if (isClosed()) {
     return [](AudioBus *, int) {};
   }
 
@@ -109,6 +117,14 @@ AudioNodeManager* BaseAudioContext::getNodeManager() {
   return nodeManager_.get();
 }
 
+bool BaseAudioContext::isRunning() const {
+  return state_ == ContextState::RUNNING;
+}
+
+bool BaseAudioContext::isClosed() const {
+  return state_ == ContextState::CLOSED;
+}
+
 std::string BaseAudioContext::toString(ContextState state) {
   switch (state) {
     case ContextState::SUSPENDED:

packages/react-native-audio-api/common/cpp/core/BaseAudioContext.h

@@ -31,6 +31,7 @@ class IOSAudioPlayer;
 class BaseAudioContext {
  public:
   BaseAudioContext();
+  ~BaseAudioContext();
   std::string getState();
   [[nodiscard]] int getSampleRate() const;
   [[nodiscard]] double getCurrentTime() const;
@@ -54,6 +55,8 @@ class BaseAudioContext {
   std::function<void(AudioBus *, int)> renderAudio();
 
   AudioNodeManager* getNodeManager();
+  bool isRunning() const;
+  bool isClosed() const;
 
  protected:
   static std::string toString(ContextState state);