// This is called periodically by the media server.
static bool audioProcessing(void *clientdata, short int *audioInputOutput, int numberOfSamples, int samplerate) {
SuperpoweredShortIntToFloat(audioInputOutput, inputBufferFloat, numberOfSamples); // Converting the 16-bit integer samples to 32-bit floating point.
frequencyDomain->addInput(inputBufferFloat, numberOfSamples); // Input goes to the frequency domain.
// In the frequency domain we are working with 1024 magnitudes and phases for every channel (left, right), if the fft size is 2048.
while (frequencyDomain->timeDomainToFrequencyDomain(magnitudeLeft, magnitudeRight, phaseLeft, phaseRight)) {
// You can work with frequency domain data from this point.
// This is just a quick example: we remove the magnitude of the first 20 bins, meaning total bass cut between 0-430 Hz.
memset(magnitudeLeft, 0, 80);
memset(magnitudeRight, 0, 80);
// We are done working with frequency domain data. Let's go back to the time domain.
// Check if we have enough room in the fifo buffer for the output. If not, move the existing audio data back to the buffer's beginning.
if (fifoOutputLastSample + stepSize >= fifoCapacity) { // This will be true for every 100th iteration only, so we save precious memory bandwidth.
int samplesInFifo = fifoOutputLastSample - fifoOutputFirstSample;
if (samplesInFifo > 0) memmove(fifoOutput, fifoOutput + fifoOutputFirstSample * 2, samplesInFifo * sizeof(float) * 2);
fifoOutputFirstSample = 0;
fifoOutputLastSample = samplesInFifo;
};
// Transforming back to the time domain.
frequencyDomain->frequencyDomainToTimeDomain(magnitudeLeft, magnitudeRight, phaseLeft, phaseRight, fifoOutput + fifoOutputLastSample * 2);
frequencyDomain->advance();
fifoOutputLastSample += stepSize;
};
// If we have enough samples in the fifo output buffer, pass them to the audio output.
if (fifoOutputLastSample - fifoOutputFirstSample >= numberOfSamples) {
SuperpoweredFloatToShortInt(fifoOutput + fifoOutputFirstSample * 2, audioInputOutput, numberOfSamples);
fifoOutputFirstSample += numberOfSamples;
return true;
} else return false;
}
extern "C" JNIEXPORT jdouble Java_com_juztoss_rhythmo_audio_BpmDetector_detect(JNIEnv *env,
jobject instance,
jstring source
) {
const char *path = env->GetStringUTFChars(source, JNI_FALSE);
SuperpoweredDecoder *decoder = new SuperpoweredDecoder();
const char *openError = decoder->open(path, false, 0, 0);
if (openError) {
__android_log_print(ANDROID_LOG_ERROR, __func__, " Decoder error, path %s, error: %s", path, openError);
delete decoder;
env->ReleaseStringUTFChars(source, path);
return -1;
};
env->ReleaseStringUTFChars(source, path);
const int samplesToDetect = 2097152; //The pow of 2 in case the fourier transform inside of the detector need it
int64_t duration = decoder->durationSamples;
int64_t start = duration / 2 - samplesToDetect / 2;
int64_t end = start + samplesToDetect;
if(start <= 0)
{
start = 0;
end = decoder->durationSamples;
}
decoder->seek(start, false);
SuperpoweredOfflineAnalyzer * analyzer = new SuperpoweredOfflineAnalyzer(decoder->samplerate, 0, decoder->durationSeconds);
// Create a buffer for the 16-bit integer samples coming from the decoder.
short int *intBuffer = (short int *)malloc(decoder->samplesPerFrame * 2 * sizeof(short int) + 16384);
// Create a buffer for the 32-bit floating point samples required by the effect.
float *floatBuffer = (float *)malloc(decoder->samplesPerFrame * 2 * sizeof(float) + 1024);
// Processing.
while (decoder->samplePosition <= end) {
// Decode one frame. samplesDecoded will be overwritten with the actual decoded number of samples.
unsigned int samplesDecoded = decoder->samplesPerFrame;
if (decoder->decode(intBuffer, &samplesDecoded) == SUPERPOWEREDDECODER_ERROR) break;
if (samplesDecoded < 1) break;
// Convert the decoded PCM samples from 16-bit integer to 32-bit floating point.
SuperpoweredShortIntToFloat(intBuffer, floatBuffer, samplesDecoded);
// Submit samples to the analyzer.
analyzer->process(floatBuffer, samplesDecoded);
};
// Get the result.
float bpm;
analyzer->getresults(NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &bpm, NULL, NULL);
// Cleanup.
delete decoder;
delete analyzer;
free(intBuffer);
free(floatBuffer);
return bpm;
}
