Nsound  0.9.4
Public Member Functions | Protected Attributes | List of all members
Nsound::Filter Class Referenceabstract

Base class for IIR Filters, defines the interface. More...

#include <Nsound/Filter.h>

Inheritance diagram for Nsound::Filter:
Inheritance graph
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Public Member Functions

 Filter (const float64 &sample_rate)
 
virtual ~Filter ()
 
void setRealtime (bool flag)
 
AudioStream filter (const AudioStream &x)
 
AudioStream filter (const AudioStream &x, const float64 &frequency)
 
AudioStream filter (const AudioStream &x, const Buffer &frequencies)
 
Buffer filter (const Buffer &x)
 
Buffer filter (const Buffer &x, const float64 &frequency)
 
Buffer filter (const Buffer &x, const Buffer &frequencies)
 
virtual float64 filter (const float64 &x)=0
 
virtual float64 filter (const float64 &x, const float64 &frequency)=0
 
Buffer getFrequencyAxis (const uint32 n_fft=8192)
 
Buffer getFrequencyResponse (const uint32 n_fft=8192)
 
Buffer getImpulseResponse (const uint32 n_samples=8192)
 
virtual uint32 getKernelSize () const
 
Buffer getPhaseResponse ()
 
float64 getSampleRate () const
 
void plot (boolean show_phase=false)
 
virtual void reset ()=0
 

Protected Attributes

float64 sample_rate_
 
float64 two_pi_over_sample_rate_
 
float64 sample_time_
 
uint32 kernel_size_
 
bool is_realtime_
 

Detailed Description

Base class for IIR Filters, defines the interface.

Definition at line 49 of file Filter.h.

Constructor & Destructor Documentation

Filter::Filter ( const float64 sample_rate)

Definition at line 41 of file Filter.cc.

42  :
43  sample_rate_(sample_rate),
44  two_pi_over_sample_rate_(2.0 * M_PI / sample_rate),
45  sample_time_(1.0 / sample_rate),
46  kernel_size_(0),
47  is_realtime_(false)
48 {
49 }
float64 sample_time_
Definition: Filter.h:115
#define M_PI
Definition: Nsound.h:121
uint32 kernel_size_
Definition: Filter.h:116
bool is_realtime_
Definition: Filter.h:118
float64 two_pi_over_sample_rate_
Definition: Filter.h:114
float64 sample_rate_
Definition: Filter.h:113
virtual Nsound::Filter::~Filter ( )
inlinevirtual

Definition at line 55 of file Filter.h.

55 {};

Member Function Documentation

void Nsound::Filter::setRealtime ( bool  flag)
inline

Definition at line 57 of file Filter.h.

References is_realtime_.

57 {is_realtime_ = flag;}
bool is_realtime_
Definition: Filter.h:118
AudioStream Filter::filter ( const AudioStream x)

Definition at line 53 of file Filter.cc.

References Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), is_realtime_, M_THROW, and reset().

Referenced by Nsound::FilterHighPassIIR::filter(), Nsound::FilterHighPassFIR::filter(), Nsound::FilterLowPassFIR::filter(), Nsound::FilterLowPassIIR::filter(), Nsound::FilterTone::filter(), Nsound::FilterDelay::filter(), Nsound::FilterAllPass::filter(), Nsound::FilterMovingAverage::filter(), Nsound::FilterFlanger::filter(), filter(), Nsound::FilterCombLowPassFeedback::filter(), Nsound::FilterBandPassVocoder::filter(), Nsound::FilterPhaser::filter(), Nsound::FilterBandPassFIR::filter(), Nsound::FilterBandRejectFIR::filter(), Nsound::FilterBandRejectIIR::filter(), Nsound::FilterBandPassIIR::filter(), Nsound::FilterStageIIR::filter(), Nsound::FilterLeastSquaresFIR::filter(), Nsound::FilterIIR::filter(), and getImpulseResponse().

54 {
55  if(!is_realtime_) reset();
56 
57  uint32 n_channels = x.getNChannels();
58 
59  if(is_realtime_ && n_channels > 1)
60  {
61  M_THROW("In real-time mode, a filter per audio channel must be used!");
62  }
63 
64  AudioStream y(x.getSampleRate(), n_channels);
65 
66  for(uint32 channel = 0; channel < n_channels; ++channel)
67  {
68  y[channel] = filter(x[channel]);
69  }
70 
71  return y;
72 }
unsigned int uint32
Definition: Nsound.h:153
float64 getSampleRate() const
Returns the sample rate of the stream.
Definition: AudioStream.h:217
virtual void reset()=0
uint32 getNChannels(void) const
Returns the number of audio channels in the stream.
Definition: AudioStream.h:212
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
#define M_THROW(message)
Definition: Macros.h:108
bool is_realtime_
Definition: Filter.h:118
AudioStream Filter::filter ( const AudioStream x,
const float64 frequency 
)

Definition at line 76 of file Filter.cc.

References filter(), Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), is_realtime_, M_THROW, and reset().

77 {
78  if(!is_realtime_) reset();
79 
80  uint32 n_channels = x.getNChannels();
81 
82  if(is_realtime_ && n_channels > 1)
83  {
84  M_THROW("In real-time mode, a filter per audio channel must be used!");
85  }
86 
87  AudioStream y(x.getSampleRate(), n_channels);
88 
89  for(uint32 channel = 0; channel < n_channels; ++channel)
90  {
91  y[channel] = filter(x[channel], frequency);
92  }
93 
94  return y;
95 }
unsigned int uint32
Definition: Nsound.h:153
float64 getSampleRate() const
Returns the sample rate of the stream.
Definition: AudioStream.h:217
virtual void reset()=0
uint32 getNChannels(void) const
Returns the number of audio channels in the stream.
Definition: AudioStream.h:212
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
#define M_THROW(message)
Definition: Macros.h:108
bool is_realtime_
Definition: Filter.h:118
AudioStream Filter::filter ( const AudioStream x,
const Buffer frequencies 
)

Definition at line 99 of file Filter.cc.

References filter(), Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), is_realtime_, M_THROW, and reset().

100 {
101  if(!is_realtime_) reset();
102 
103  uint32 n_channels = x.getNChannels();
104 
105  if(is_realtime_ && n_channels > 1)
106  {
107  M_THROW("In real-time mode, a filter per audio channel must be used!");
108  }
109 
110  AudioStream y(x.getSampleRate(), n_channels);
111 
112  for(uint32 channel = 0; channel < n_channels; ++channel)
113  {
114  y[channel] = filter(x[channel], frequency);
115  }
116 
117  return y;
118 }
unsigned int uint32
Definition: Nsound.h:153
float64 getSampleRate() const
Returns the sample rate of the stream.
Definition: AudioStream.h:217
virtual void reset()=0
uint32 getNChannels(void) const
Returns the number of audio channels in the stream.
Definition: AudioStream.h:212
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
#define M_THROW(message)
Definition: Macros.h:108
bool is_realtime_
Definition: Filter.h:118
Buffer Filter::filter ( const Buffer x)

Definition at line 122 of file Filter.cc.

References filter(), Nsound::Buffer::getLength(), is_realtime_, and reset().

123 {
124  if(!is_realtime_) reset();
125 
126  Buffer y(x.getLength());
127 
128  uint32 x_samples = x.getLength();
129 
130  for(uint32 i = 0; i < x_samples; ++i)
131  {
132  y << filter(x[i]);
133  }
134 
135  return y;
136 }
unsigned int uint32
Definition: Nsound.h:153
uint32 getLength() const
Returns the number of samples in the Buffer.
Definition: Buffer.h:587
virtual void reset()=0
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
bool is_realtime_
Definition: Filter.h:118
A Buffer for storing audio samples.
Definition: Buffer.h:60
Buffer Filter::filter ( const Buffer x,
const float64 frequency 
)

Definition at line 140 of file Filter.cc.

References Nsound::Buffer::begin(), Nsound::Buffer::end(), filter(), Nsound::Buffer::getLength(), is_realtime_, and reset().

141 {
142  if(!is_realtime_) reset();
143 
144  Buffer::const_iterator itor = x.begin();
145  Buffer::const_iterator end = x.end();
146 
147  Buffer y(x.getLength());
148 
149  while(itor != end)
150  {
151  y << filter(*itor, frequency);
152 
153  ++itor;
154  }
155 
156  return y;
157 }
uint32 getLength() const
Returns the number of samples in the Buffer.
Definition: Buffer.h:587
virtual void reset()=0
iterator end()
Retruns the itreator at the end of the Buffer.
Definition: Buffer.h:348
FloatVector::const_iterator const_iterator
Definition: Buffer.h:70
iterator begin()
Retruns the itreator at the start of the Buffer.
Definition: Buffer.h:285
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
bool is_realtime_
Definition: Filter.h:118
A Buffer for storing audio samples.
Definition: Buffer.h:60
Buffer Filter::filter ( const Buffer x,
const Buffer frequencies 
)

Definition at line 161 of file Filter.cc.

References Nsound::Buffer::begin(), Nsound::Buffer::cbegin(), Nsound::Buffer::end(), filter(), Nsound::Buffer::getLength(), is_realtime_, and reset().

162 {
163  if(!is_realtime_) reset();
164 
165  Buffer::const_circular_iterator freq = frequencies.cbegin();
166 
167  Buffer::const_iterator itor = x.begin();
168  Buffer::const_iterator end = x.end();
169 
170  Buffer y(x.getLength());
171 
172  while(itor != end)
173  {
174  y << filter(*itor, *freq);
175 
176  ++itor;
177  ++freq;
178  }
179 
180  return y;
181 }
circular_iterator cbegin()
Retruns the itreator at the start of the Buffer.
Definition: Buffer.h:318
uint32 getLength() const
Returns the number of samples in the Buffer.
Definition: Buffer.h:587
virtual void reset()=0
iterator end()
Retruns the itreator at the end of the Buffer.
Definition: Buffer.h:348
FloatVector::const_iterator const_iterator
Definition: Buffer.h:70
iterator begin()
Retruns the itreator at the start of the Buffer.
Definition: Buffer.h:285
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
bool is_realtime_
Definition: Filter.h:118
A Buffer for storing audio samples.
Definition: Buffer.h:60
virtual float64 Nsound::Filter::filter ( const float64 x)
pure virtual
virtual float64 Nsound::Filter::filter ( const float64 x,
const float64 frequency 
)
pure virtual
Buffer Filter::getFrequencyAxis ( const uint32  n_fft = 8192)

Definition at line 185 of file Filter.cc.

References Nsound::FFTransform::roundUp2(), and sample_rate_.

Referenced by main(), plot(), and Nsound::FilterIIR::savePlot().

186 {
187  uint32 fft_chunk_size = FFTransform::roundUp2(
188  static_cast<int32>(n_fft));
189 
190  uint32 n_samples = fft_chunk_size / 2 + 1;
191 
192  float64 f_step = (1.0 / (static_cast<float64>(fft_chunk_size) / 2.0))
193  * (sample_rate_ / 2.0);
194 
195  Buffer f_axis;
196 
197  float64 f = 0.0;
198 
199  for(uint32 i = 0; i < n_samples; ++i)
200  {
201  f_axis << f;
202  f += f_step;
203  }
204 
205  return f_axis;
206 };
unsigned int uint32
Definition: Nsound.h:153
double float64
Definition: Nsound.h:146
static int32 roundUp2(int32 raw)
Returns nearest power of 2 >= raw.
Definition: FFTransform.cc:274
A Buffer for storing audio samples.
Definition: Buffer.h:60
float64 sample_rate_
Definition: Filter.h:113
Buffer Filter::getFrequencyResponse ( const uint32  n_fft = 8192)

Definition at line 210 of file Filter.cc.

References Nsound::FFTransform::fft(), getImpulseResponse(), and sample_rate_.

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), FilterLeastSquaresFIR_UnitTest(), Nsound::FilterIIR::getRMS(), main(), plot(), and Nsound::FilterIIR::savePlot().

211 {
213 
214 //~ fft.setWindow(HANNING);
215 
216  FFTChunkVector vec;
217 
218  vec = fft.fft(getImpulseResponse(), n_fft);
219 
220  return vec[0].getMagnitude();
221 }
Buffer getImpulseResponse(const uint32 n_samples=8192)
Definition: Filter.cc:225
A Class that performes the Fast Fouier Transfrom on a Buffer.
Definition: FFTransform.h:57
std::vector< FFTChunk > FFTChunkVector
Definition: FFTChunk.h:119
float64 sample_rate_
Definition: Filter.h:113
Buffer Filter::getImpulseResponse ( const uint32  n_samples = 8192)

Definition at line 225 of file Filter.cc.

References filter(), is_realtime_, and reset().

Referenced by getFrequencyResponse(), Nsound::FilterHighPassFIR::getImpulseResponse(), Nsound::FilterLowPassFIR::getImpulseResponse(), Nsound::FilterLeastSquaresFIR::getImpulseResponse(), Nsound::FilterIIR::getImpulseResponse(), and getPhaseResponse().

226 {
227  if(!is_realtime_) reset();
228 
229  Buffer response(n_samples);
230 
231  response << filter(1.0);
232 
233  for(uint32 i = 1; i < n_samples; ++i)
234  {
235  response << filter(0.0);
236  }
237 
238  if(!is_realtime_) reset();
239 
240  return response;
241 }
unsigned int uint32
Definition: Nsound.h:153
virtual void reset()=0
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
bool is_realtime_
Definition: Filter.h:118
A Buffer for storing audio samples.
Definition: Buffer.h:60
virtual uint32 Nsound::Filter::getKernelSize ( ) const
inlinevirtual
Buffer Filter::getPhaseResponse ( )

Definition at line 245 of file Filter.cc.

References Nsound::FFTransform::fft(), getImpulseResponse(), Nsound::Buffer::getLength(), sample_rate_, and Nsound::Buffer::subbuffer().

Referenced by plot().

246 {
247  uint32 n_samples = static_cast<uint32>(sample_rate_ * 2);
248 
249  FFTransform fft(n_samples);
250 
251  FFTChunkVector vec;
252 
253  vec = fft.fft(getImpulseResponse(), n_samples);
254 
255  Buffer phase = vec[0].getPhase();
256 
257  return phase.subbuffer(0, phase.getLength() / 2 + 1);
258 }
Buffer subbuffer(uint32 start_index, uint32 n_samples=0) const
Slice the Buffer.
Definition: Buffer.cc:2073
unsigned int uint32
Definition: Nsound.h:153
uint32 getLength() const
Returns the number of samples in the Buffer.
Definition: Buffer.h:587
Buffer getImpulseResponse(const uint32 n_samples=8192)
Definition: Filter.cc:225
A Class that performes the Fast Fouier Transfrom on a Buffer.
Definition: FFTransform.h:57
A Buffer for storing audio samples.
Definition: Buffer.h:60
std::vector< FFTChunk > FFTChunkVector
Definition: FFTChunk.h:119
float64 sample_rate_
Definition: Filter.h:113
float64 Nsound::Filter::getSampleRate ( ) const
inline

Definition at line 102 of file Filter.h.

References sample_rate_.

102 { return sample_rate_; };
float64 sample_rate_
Definition: Filter.h:113
void Filter::plot ( boolean  show_phase = false)

Definition at line 262 of file Filter.cc.

References Nsound::Plotter::figure(), Nsound::Buffer::getdB(), getFrequencyAxis(), getFrequencyResponse(), Nsound::Buffer::getMax(), getPhaseResponse(), Nsound::Plotter::plot(), Nsound::Plotter::subplot(), Nsound::Plotter::xlabel(), Nsound::Plotter::ylabel(), and Nsound::Plotter::ylim().

Referenced by main(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassVocoder::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterBandRejectIIR::plot(), and Nsound::FilterParametricEqualizer::plot().

263 {
264  Buffer x = getFrequencyAxis();
266 
267  Plotter pylab;
268 
269  pylab.figure();
270 
271  uint32 n_rows = 1;
272  uint32 n_cols = 1;
273 
274  if(show_phase)
275  {
276  n_rows = 2;
277  }
278 
279  pylab.subplot(n_rows, n_cols, 1);
280 
281  // Frequency response
282  pylab.plot(x,fr, "blue");
283 
284  pylab.xlabel("Frequency (Hz)");
285  pylab.ylabel("Frequency Response (dB)");
286 
287  // Phase response
288  if(show_phase)
289  {
290  pylab.subplot(n_rows, n_cols, 2);
291 
292  Buffer pr = getPhaseResponse().getdB();
293 
294  pylab.plot(x,pr);
295 
296  pylab.xlabel("Frequency (Hz)");
297  pylab.ylabel("Phase Response (dB)");
298  }
299 
300  float64 ymax = fr.getMax();
301  float64 height = ymax - -60.0;
302 
303  pylab.ylim(-60.0, ymax + 0.05 * height);
304 }
unsigned int uint32
Definition: Nsound.h:153
void xlabel(const std::string &label, const std::string &kwargs="")
Add a label x axis.
Definition: Plotter.cc:1154
void plot(const Buffer &y, const std::string &fmt="", const std::string &kwargs="")
Plots the Buffer on the current figure.
Definition: Plotter.cc:765
void figure(const std::string &kwargs="") const
Creates a new figure window to plot in.
Definition: Plotter.cc:455
Buffer getPhaseResponse()
Definition: Filter.cc:245
double float64
Definition: Nsound.h:146
Axes subplot(const uint32 n_rows, const uint32 n_cols, const uint32 n, const std::string &kwargs="", Axes *sharex=NULL, Axes *sharey=NULL)
Creates a figure in a subplot, subplot(A, B, C, **kwargs)
Definition: Plotter.cc:1031
void ylim(const float64 &ymin, const float64 &ymax)
Definition: Plotter.cc:422
Buffer getFrequencyAxis(const uint32 n_fft=8192)
Definition: Filter.cc:185
void ylabel(const std::string &label, const std::string &kwargs="")
Add a label y axis.
Definition: Plotter.cc:1180
A Buffer for storing audio samples.
Definition: Buffer.h:60
Buffer getFrequencyResponse(const uint32 n_fft=8192)
Definition: Filter.cc:210
float64 getMax() const
Returns the maximum sample value in the Buffer.
Definition: Buffer.cc:951
Buffer getdB() const
Returns the Buffer in dB.
Definition: Buffer.h:487
virtual void Nsound::Filter::reset ( )
pure virtual

Member Data Documentation

float64 Nsound::Filter::sample_rate_
protected

Definition at line 113 of file Filter.h.

Referenced by Nsound::FilterPhaser::filter(), Nsound::FilterCombLowPassFeedback::filter(), Nsound::FilterDelay::filter(), Nsound::FilterAllPass::FilterAllPass(), Nsound::FilterCombLowPassFeedback::FilterCombLowPassFeedback(), Nsound::FilterDelay::FilterDelay(), Nsound::FilterFlanger::FilterFlanger(), Nsound::FilterPhaser::FilterPhaser(), Nsound::FilterSlinky::FilterSlinky(), getFrequencyAxis(), getFrequencyResponse(), getPhaseResponse(), getSampleRate(), Nsound::FilterStageIIR::makeIIRKernelHelper(), Nsound::FilterHighPassFIR::makeKernel(), Nsound::FilterStageIIR::makeKernel(), Nsound::FilterBandPassVocoder::makeKernel(), Nsound::FilterLeastSquaresFIR::makeKernel(), Nsound::FilterParametricEqualizer::makeKernel(), Nsound::FilterPhaser::operator=(), Nsound::FilterLeastSquaresFIR::operator=(), Nsound::FilterFlanger::operator=(), Nsound::FilterIIR::operator=(), Nsound::FilterLowPassMoogVcf::plot(), Nsound::FilterPhaser::plot(), Nsound::FilterTone::plot(), Nsound::FilterHighPassIIR::plot(), Nsound::FilterLowPassIIR::plot(), Nsound::FilterCombLowPassFeedback::plot(), Nsound::FilterLowPassFIR::plot(), Nsound::FilterHighPassFIR::plot(), Nsound::FilterAllPass::plot(), Nsound::FilterBandPassFIR::plot(), Nsound::FilterLeastSquaresFIR::plot(), Nsound::FilterFlanger::plot(), Nsound::FilterBandRejectFIR::plot(), Nsound::FilterBandRejectIIR::plot(), Nsound::FilterBandPassIIR::plot(), Nsound::FilterParametricEqualizer::plot(), Nsound::FilterLowPassIIR::setCutoff(), and Nsound::FilterLeastSquaresFIR::setWindow().

float64 Nsound::Filter::two_pi_over_sample_rate_
protected
float64 Nsound::Filter::sample_time_
protected

Definition at line 115 of file Filter.h.

Referenced by Nsound::FilterLowPassMoogVcf::_make_filter().

uint32 Nsound::Filter::kernel_size_
protected
bool Nsound::Filter::is_realtime_
protected

The documentation for this class was generated from the following files: