[PowerPlay] Add Local Playback and support (#2363)

* Add playback seeking and progress tracking.

* Add support for loading and playing local WAV files

* Update audio engine to probe and return WAV metadata during asset loading

* Code nits

* Cleanup: Remove unnecessary comments and metadata

* Remove redundant comments and documentation blocks across `MainActivity.kt` and `PowerPlayMultiPlayer.cpp`.
* Delete an unused Kotlin compiler session file.

* Set audio usage and content type for PowerPlayMultiPlayer

* refactor: remove redundant whitespace and empty lines in MainActivity.kt

* parselib: Support WAVEFORMATEXTENSIBLE and improve WAV parsing robustness

Author: madebymozart

samples/parselib/src/main/cpp/wav/WavFmtChunkHeader.cpp

@@ -64,11 +64,36 @@ void WavFmtChunkHeader::read(InputStream *stream) {
     stream->read(&mBlockAlign, sizeof(mBlockAlign));
     stream->read(&mSampleSize, sizeof(mSampleSize));
 
-    if (mEncodingId != ENCODING_PCM && mEncodingId != ENCODING_IEEE_FLOAT) {
-        // only read this if NOT PCM
+    if (mEncodingId == ENCODING_EXTENSIBLE) {
         stream->read(&mExtraBytes, sizeof(mExtraBytes));
+
+        RiffInt16 validBitsPerSample;
+        stream->read(&validBitsPerSample, sizeof(validBitsPerSample));
+
+        RiffInt32 channelMask;
+        stream->read(&channelMask, sizeof(channelMask));
+
+        RiffInt16 subFormatEncoding;
+        stream->read(&subFormatEncoding, sizeof(subFormatEncoding));
+        mEncodingId = subFormatEncoding;
+
+        stream->advance(14);
+    } else if (mEncodingId != ENCODING_PCM &&
+        mEncodingId != ENCODING_IEEE_FLOAT) {
+
+        // other non-PCM formats (e.g., ADPCM)
+        stream->read(&mExtraBytes, sizeof(mExtraBytes));
+
+        // Skip any remaining extension data beyond the 18 bytes already read
+        int bytesRemaining = mChunkSize - 18;
+        if (bytesRemaining > 0) {
+            stream->advance(bytesRemaining);
+        }
     } else {
         mExtraBytes = (short) (mChunkSize - 16);
+        if (mExtraBytes > 0) {
+            stream->advance(mExtraBytes);
+        }
     }
 }
 

samples/parselib/src/main/cpp/wav/WavFmtChunkHeader.h

@@ -33,6 +33,7 @@ class WavFmtChunkHeader : public WavChunkHeader {
     static const short ENCODING_PCM = 1;
     static const short ENCODING_ADPCM = 2; // Microsoft ADPCM Format
     static const short ENCODING_IEEE_FLOAT = 3; // samples from -1.0 -> 1.0
+    static const short ENCODING_EXTENSIBLE = (short)0xFFFE; // WAVEFORMATEXTENSIBLE
 
     RiffInt16 mEncodingId;  /** Microsoft WAV encoding ID (see above) */
     RiffInt16 mNumChannels;

samples/parselib/src/main/cpp/wav/WavStreamReader.cpp

@@ -202,16 +202,18 @@ int WavStreamReader::getDataFloat_PCM24(float *buff, int numFrames) {
     static constexpr float kSampleFullScale = (float) 0x80000000;
     static constexpr float kInverseScale = 1.0f / kSampleFullScale;
 
+    int samplesRead = 0;
     uint8_t buffer[3];
     for(int sampleIndex = 0; sampleIndex < numSamples; sampleIndex++) {
         if (mStream->read(buffer, 3) < 3) {
             break; // no more data
         }
         int32_t sample = (buffer[0] << 8) | (buffer[1] << 16) | (buffer[2] << 24);
         buff[sampleIndex] = (float)sample * kInverseScale;
+        samplesRead++;
     }
 
-    return numFrames;
+    return samplesRead / numChannels;
 }
 
 /**

samples/parselib/src/main/cpp/wav/WavStreamReader.h

@@ -35,17 +35,23 @@ class WavStreamReader {
 public:
     WavStreamReader(InputStream *stream);
 
-    int getSampleRate() { return mFmtChunk->mSampleRate; }
+    bool isValid() { return mFmtChunk != nullptr && mDataChunk != nullptr; }
+
+    int getSampleRate() { return mFmtChunk != nullptr ? mFmtChunk->mSampleRate : 0; }
 
     int getNumSampleFrames() {
+        if (mDataChunk == nullptr || mFmtChunk == nullptr ||
+            mFmtChunk->mSampleSize == 0 || mFmtChunk->mNumChannels == 0) {
+            return 0;
+        }
         return mDataChunk->mChunkSize / (mFmtChunk->mSampleSize / 8) / mFmtChunk->mNumChannels;
     }
 
-    int getNumChannels() { return mFmtChunk != 0 ? mFmtChunk->mNumChannels : 0; }
+    int getNumChannels() { return mFmtChunk != nullptr ? mFmtChunk->mNumChannels : 0; }
 
     int getSampleEncoding();
 
-    int getBitsPerSample() { return mFmtChunk->mSampleSize; }
+    int getBitsPerSample() { return mFmtChunk != nullptr ? mFmtChunk->mSampleSize : 0; }
 
     void parse();
 

samples/powerplay/src/main/assets/song1.wav

@@ -359,7 +359,67 @@ Java_com_google_oboe_samples_powerplay_engine_PowerPlayAudioPlayer_getDurationMi
     return (jlong) player.getDurationMillis(index);
 }
 
+/**
+ * Native (JNI) implementation of PowerPlayAudioPlayer.getWavFileInfoNative()
+ * Parses WAV header and returns audio properties without loading sample data.
+ * Returns an intArray: [sampleRate, numChannels, bitsPerSample, encoding, numFramesHigh, numFramesLow]
+ */
+JNIEXPORT jintArray JNICALL
+Java_com_google_oboe_samples_powerplay_engine_PowerPlayAudioPlayer_getWavFileInfoNative(
+        JNIEnv *env,
+        jobject,
+        jbyteArray bytearray) {
+    const int32_t len = env->GetArrayLength(bytearray);
+    auto *buf = new unsigned char[len];
+    env->GetByteArrayRegion(bytearray, 0, len, reinterpret_cast<jbyte *>(buf));
+
+    MemInputStream stream(buf, len);
+    WavStreamReader reader(&stream);
+    reader.parse();
+
+    if (!reader.isValid()) {
+        __android_log_print(ANDROID_LOG_ERROR, TAG,
+                "getWavFileInfoNative: WAV parse failed - missing fmt or data chunk");
+        jintArray result = env->NewIntArray(6);
+        jint values[6] = {0, 0, 0, 0, 0, 0};
+        env->SetIntArrayRegion(result, 0, 6, values);
+        delete[] buf;
+        return result;
+    }
+
+    int32_t sampleRate = reader.getSampleRate();
+    int32_t numChannels = reader.getNumChannels();
+    int32_t bitsPerSample = reader.getBitsPerSample();
+    int32_t encoding = reader.getSampleEncoding();
+    int64_t numFrames = static_cast<int64_t>(reader.getNumSampleFrames());
+
+    // Pack into int array: [sampleRate, numChannels, bitsPerSample, encoding, numFramesHigh, numFramesLow]
+    jintArray result = env->NewIntArray(6);
+    jint values[6] = {
+        sampleRate,
+        numChannels,
+        bitsPerSample,
+        encoding,
+        static_cast<jint>((numFrames >> 32) & 0xFFFFFFFF),
+        static_cast<jint>(numFrames & 0xFFFFFFFF)
+    };
+    env->SetIntArrayRegion(result, 0, 6, values);
+
+    delete[] buf;
+    return result;
+}
+
+/**
+ * Native (JNI) implementation of PowerPlayAudioPlayer.removeSampleSourceNative()
+ */
+JNIEXPORT jboolean JNICALL
+Java_com_google_oboe_samples_powerplay_engine_PowerPlayAudioPlayer_removeSampleSourceNative(
+        JNIEnv *env,
+        jobject,
+        jint index) {
+    return player.removeSampleSource(index);
+}
+
 #ifdef __cplusplus
 }
 #endif
-

samples/powerplay/src/main/assets/song2.wav

@@ -55,6 +55,8 @@ bool PowerPlayMultiPlayer::openStream(oboe::PerformanceMode performanceMode) {
             ->setFormat(AudioFormat::Float)
             ->setSampleRate(48000)
             ->setPerformanceMode(performanceMode)
+            ->setUsage(Usage::Media)
+            ->setContentType(ContentType::Music)
             ->setFramesPerDataCallback(128)
             ->setSharingMode(SharingMode::Exclusive);
 
@@ -320,3 +322,31 @@ int64_t PowerPlayMultiPlayer::getDurationMillis(int32_t index) {
 
     return (static_cast<int64_t>(sampleBuffer->getNumSamples() / channelCount) * 1000) / sampleRate;
 }
+
+bool PowerPlayMultiPlayer::removeSampleSource(int32_t index) {
+    if (index < 0 || index >= mSampleSources.size()) {
+        __android_log_print(ANDROID_LOG_ERROR, TAG,
+                            "removeSampleSource: Invalid index %d (size=%zu)",
+                            index, mSampleSources.size());
+        return false;
+    }
+
+    if (mSampleSources[index]->isPlaying()) {
+        mSampleSources[index]->setStopMode(false);
+    }
+
+    delete mSampleSources[index];
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdelete-non-abstract-non-virtual-dtor"
+    delete mSampleBuffers[index];
+#pragma GCC diagnostic pop
+
+    mSampleSources.erase(mSampleSources.begin() + index);
+    mSampleBuffers.erase(mSampleBuffers.begin() + index);
+    mNumSampleBuffers--;
+
+    __android_log_print(ANDROID_LOG_INFO, TAG,
+                        "removeSampleSource: Removed index %d, %d sources remaining",
+                        index, mNumSampleBuffers);
+    return true;
+}

samples/powerplay/src/main/cpp/PowerPlayJNI.cpp

@@ -58,6 +58,8 @@ class PowerPlayMultiPlayer : public iolib::SimpleMultiPlayer {
 
     int64_t getDurationMillis(int32_t index);
 
+    bool removeSampleSource(int32_t index);
+
 private:
     class MyPresentationCallback : public oboe::AudioStreamPresentationCallback {
     public: