WSJT-X/Detector.hpp
Bill Somerville 688943e779 Fix audio input rate issue on Windows Vista
Windows Vista has a broken rate converter which gets invoked when an
input audio stream at 48kHz sampel rate is requested. I've no idea why
our application can't get exclusive access to the audio input device
and have a unconverted stream direct at 48kHz.

To get around this our down sampling filter for audio input from 48kHz
to 12kHz is disaabled by default on Windows Vista, instead we request
a 12kHz stream and process it directly.

This default behviour can be overriden by specifying the following
settings value:

[Tune]
Audio\DisableInputResampling=false

This settings value defaults to true on Windows Vista and false
everywhere else so normally needn't be present.



git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@3588 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2013-10-04 19:00:29 +00:00

68 lines
2.0 KiB
C++

#ifndef DETECTOR_HPP__
#define DETECTOR_HPP__
#include "AudioDevice.hpp"
#include <QScopedArrayPointer>
//
// output device that distributes data in predefined chunks via a signal
//
// the underlying device for this abstraction is just the buffer that
// stores samples throughout a receiving period
//
class Detector : public AudioDevice
{
Q_OBJECT;
Q_PROPERTY (bool monitoring READ isMonitoring WRITE setMonitoring);
public:
//
// if the data buffer were not global storage and fixed size then we
// might want maximum size passed as constructor arguments
//
// we down sample by a factor of 4
//
// the framesPerSignal argument is the number after down sampling
//
Detector (unsigned frameRate, unsigned periodLengthInSeconds, unsigned framesPerSignal, unsigned downSampleFactor = 4u, QObject * parent = 0);
bool isMonitoring () const {return m_monitoring;}
protected:
qint64 readData (char * /* data */, qint64 /* maxSize */)
{
return -1; // we don't produce data
}
qint64 writeData (char const * data, qint64 maxSize);
private:
// these are private because we want thread safety, must be called via Qt queued connections
Q_SLOT void open (AudioDevice::Channel channel = Mono) {AudioDevice::open (QIODevice::WriteOnly, channel);}
Q_SLOT void setMonitoring (bool newState) {m_monitoring = newState; m_bufferPos = 0;}
Q_SLOT bool reset ();
Q_SLOT void close () {AudioDevice::close ();}
Q_SIGNAL void framesWritten (qint64);
void clear (); // discard buffer contents
unsigned secondInPeriod () const;
unsigned m_frameRate;
unsigned m_period;
unsigned m_downSampleFactor;
qint32 m_framesPerSignal; // after any down sampling
bool volatile m_monitoring;
bool m_starting;
QScopedArrayPointer<short> m_buffer; // de-interleaved sample buffer
// big enough for all the
// samples for one increment of
// data (a signals worth) at
// the input sample rate
unsigned m_bufferPos;
};
#endif