How to use

limit

method

in

com.smartdevicelink.managers.audio.SampleBuffer

private Double sampleAtTargetTime(double lastOutputSample, SampleBuffer outputSampleBuffer, double outputPresentationTimeUs, double outputDurationPerSampleUs, double targetPresentationTimeUs) {
  double timeDiff = targetPresentationTimeUs - outputPresentationTimeUs;
  double index = timeDiff / outputDurationPerSampleUs;
  // the "last known sample" allows an index from -1.0 to 0
  // the index cannot exceed the last sample. it must be stored to become the "last known sample" in the next iteration
  if (index < -1.0 || Math.ceil(index) >= outputSampleBuffer.limit()) {
    return null;
  }
  if (index == -1.0) {
    // the index points exactly to the last known sample
    return lastOutputSample;
  } else if (index % 1 == 0) {
    // index has no digits. therefore current index points to a known sample
    return outputSampleBuffer.get((int) index);
  } else {
    // the first sample can be the last known one
    double first = index < 0.0 ? lastOutputSample : outputSampleBuffer.get((int) index);
    double second = outputSampleBuffer.get((int) Math.ceil(index));
    double rel = index % 1;
    // if the relative is between -1 and 0
    if (rel < 0.0) {
      rel = 1 + rel;
    }
    return first + (second - first) * rel;
  }
}

protected SampleBuffer onOutputBufferAvailable(@NonNull ByteBuffer outputBuffer) {
  double outputPresentationTimeUs = lastOutputPresentationTimeUs;
  double outputDurationPerSampleUs = 1000000.0 / (double)outputSampleRate;
  double targetPresentationTimeUs = lastTargetPresentationTimeUs;
  double targetDurationPerSampleUs = 1000000.0 / (double)targetSampleRate;
  // wrap the output buffer to make it provide audio samples
  SampleBuffer outputSampleBuffer = SampleBuffer.wrap(outputBuffer, outputSampleType, outputChannelCount, (long)outputPresentationTimeUs);
  outputSampleBuffer.position(0);
  // the buffer size is related to the output and target sample rate
  // add 2 samples to round up and add an extra sample
  int sampleSize = outputSampleBuffer.limit() * targetSampleRate / outputSampleRate + 2;
  SampleBuffer targetSampleBuffer = SampleBuffer.allocate(sampleSize, targetSampleType, ByteOrder.LITTLE_ENDIAN, (long)targetPresentationTimeUs);
  Double sample;
  do {
    sample = sampleAtTargetTime(lastOutputSample, outputSampleBuffer, outputPresentationTimeUs, outputDurationPerSampleUs, targetPresentationTimeUs);
    if (sample != null) {
      targetSampleBuffer.put(sample);
      targetPresentationTimeUs += targetDurationPerSampleUs;
    }
  } while (sample != null);
  lastTargetPresentationTimeUs = targetPresentationTimeUs;
  lastOutputPresentationTimeUs += outputSampleBuffer.limit() * outputDurationPerSampleUs;
  lastOutputSample = outputSampleBuffer.get(outputSampleBuffer.limit() - 1);
  targetSampleBuffer.limit(targetSampleBuffer.position());
  targetSampleBuffer.position(0);
  return targetSampleBuffer;
}

  @Override
  public void sendAudio(ByteBuffer data, long presentationTimeUs) {
    SampleBuffer samples = SampleBuffer.wrap(data, sampleType, presentationTimeUs);
    double timeUs = presentationTimeUs;
    double sampleDurationUs = 1000000.0 / sampleRate;
    for (int i = 0; i < samples.limit(); ++i) {
      double sample = samples.get(i);
      double edge = timeUs % 4000.0;
      if (edge > 2000.0) {
        // swap sample as it's negative expected
        sample = sample * -1.0;
      }
      edge = edge % 2000.0;
      // at the edge of a wave the sample can be lower than 0.7
      if ((sample > 0.7 && sample < 0.95) || (edge < sampleDurationUs || (2000.0 - sampleDurationUs) < edge)) {
        testFullAudioManagerDecodeFlowCorrectCounter++;
      } else {
        testFullAudioManagerDecodeFlowWrongCounter++;
      }
      timeUs += sampleDurationUs;
    }
  }
};