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/******************************************************************************
*
* Beats-per-minute (BPM) detection routine
*
* Author : Copyright (c) Olli Parviainen
* Author e-mail : oparviai @ iki.fi
* File created : 11-Jan-2003
*
* Last changed : $Date: 2003/10/13 00:35:13 $
* File revision : $Revision: 1.1 $
*
* $Id: BPMDetect.h,v 1.1 2003/10/13 00:35:13 melanie_t Exp $
*
* License :
*
* SoundTouch sound processing library
* Copyright (c) Olli Parviainen
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*****************************************************************************/
#ifndef _BPMDetect_H_
#define _BPMDetect_H_
#include <qthread.h>
/// Minimum allowed BPM rate
#define MIN_BPM 30
/// Maximum allowed BPM rate
#define MAX_BPM 230
class StreamSource;
class QWidget;
class QBPMEvent : public QEvent
{
public:
enum Type {LoaderEvent = 1002};
QBPMEvent(Type t=LoaderEvent);
~QBPMEvent();
float bpm();
void setBpm(float i_bpm);
protected:
float s_bpm;
};
/// Internal class prototype
class FIFOSampleBuffer;
/// Class for calculating BPM rate for audio data.
class BPMDetect : public QThread
{
protected:
/// Auto-correlation accumulator bins.
float *xcorr;
/// Amplitude envelope sliding average approximation level accumulator
float envelopeAccu;
/// RMS volume sliding average approximation level accumulator
float RMSVolumeAccu;
/// Sample average counter.
int decimateCount;
/// Sample average accumulator for FIFO-like decimation.
int decimateSum;
/// Decimate sound by this coefficient to reach approx. 500 Hz.
int decimateBy;
/// Auto-correlation window length
int windowLen;
/// Beginning of auto-correlation window: Autocorrelation isn't being updated for
/// the first these many correlation bins.
int windowStart;
/// FIFO-buffer for decimated processing samples.
FIFOSampleBuffer *buffer;
/// Initialize the class for WAV file.
void init(StreamSource *source);
/// Updates auto-correlation function for given number of decimated samples that
/// are read from the internal 'buffer' pipe (samples aren't removed from the pipe
/// though).
void updateXCorr(const int process_samples /// How many samples are processed.
);
/// Decimates samples to approx. 500 Hz.
///
/// \return Number of output samples.
int decimate(short *dest, ///< Destination buffer
const short *src, ///< Source sample buffer
int numsamples ///< Number of source samples.
);
/// Reads and prepares a block of samples for processing. Stereo sound is converted
/// to mono and sound data is then decimated down to approx. 500 Hz.
///
/// \return Number of samples moved to outBuffer.
int inputSamples(StreamSource *source, ///< WAV file where data is read from
short *outBuffer ///< Buffer for samples.
);
/// Processes block of samples: Envelopes the samples and then
/// updates the autocorrelation estimation.
void processBlock(short *samples, ///< Pointer to input/working data buffer
int numSamples ///< Number of samples in buffer
);
/// Calculates amplitude envelope for the buffer of samples.
/// Result is outputted in 'samples.
void calcEnvelope(short *samples, ///< Pointer to input/output data buffer
int numsamples ///< Number of samples in buffer
);
StreamSource *s_source;
/// Analyzes the WAV file data and returns BPM rate. Notice that the
/// WAV audio data has to be in 16bit sample format.
///
/// \return Beats-per-minute rate, or zero if detection failed.
float detectBpm(StreamSource *source);
float s_res;
bool s_abort;
QWidget *s_parent;
public:
/// Constructor.
BPMDetect(QWidget *parent, StreamSource *source);
/// Destructor.
virtual ~BPMDetect();
void run(void);
float result();
void abort();
};
#endif // _BPMDetect_H_
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