Nsound  0.9.4
Classes | Public Member Functions | Protected Types | Protected Attributes | List of all members
Nsound::FilterTone Class Reference

#include <Nsound/FilterTone.h>

Inheritance diagram for Nsound::FilterTone:
Inheritance graph
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Classes

struct  Kernel
 A class to store calculated kernels. More...
 

Public Member Functions

 FilterTone (const float64 &sample_rate, const float64 &half_power_frequency)
 
virtual ~FilterTone ()
 
AudioStream filter (const AudioStream &x)
 
AudioStream filter (const AudioStream &x, const Buffer &hp_frequencies)
 
Buffer filter (const Buffer &x)
 
Buffer filter (const Buffer &x, const Buffer &hp_frequencies)
 
float64 filter (const float64 &x)
 
float64 filter (const float64 &x, const float64 &hp_frequency)
 
float64 getFrequency () const
 
uint32 getKernelSize () const
 
void plot (boolean show_fc=true, boolean show_phase=false)
 
void reset ()
 
void makeKernel (const float64 &half_power_frequency)
 
void setRealtime (bool flag)
 
AudioStream filter (const AudioStream &x, const float64 &frequency)
 
Buffer filter (const Buffer &x, const float64 &frequency)
 
Buffer getFrequencyAxis (const uint32 n_fft=8192)
 
Buffer getFrequencyResponse (const uint32 n_fft=8192)
 
Buffer getImpulseResponse (const uint32 n_samples=8192)
 
Buffer getPhaseResponse ()
 
float64 getSampleRate () const
 
void plot (boolean show_phase=false)
 

Protected Types

typedef std::set< KernelKernelCache
 

Protected Attributes

float64 hp_frequency_
 
float64 b_
 
float64 a_
 
float64 last_output_
 
KernelCache kernel_cache_
 
float64 sample_rate_
 
float64 two_pi_over_sample_rate_
 
float64 sample_time_
 
uint32 kernel_size_
 
bool is_realtime_
 

Detailed Description

Definition at line 47 of file FilterTone.h.

Member Typedef Documentation

typedef std::set<Kernel> Nsound::FilterTone::KernelCache
protected

Definition at line 112 of file FilterTone.h.

Constructor & Destructor Documentation

FilterTone::FilterTone ( const float64 sample_rate,
const float64 half_power_frequency 
)

Definition at line 42 of file FilterTone.cc.

References reset().

43  :
44  Filter(sample_rate),
45  hp_frequency_(half_power_frequency),
46  b_(0.0),
47  a_(0.0),
48  last_output_(0.0),
50 {
51  reset();
52 }
KernelCache kernel_cache_
Definition: FilterTone.h:114
Filter(const float64 &sample_rate)
Definition: Filter.cc:41
float64 last_output_
Definition: FilterTone.h:97
float64 hp_frequency_
Definition: FilterTone.h:94
FilterTone::~FilterTone ( )
virtual

Definition at line 56 of file FilterTone.cc.

57 {
58 
59 }

Member Function Documentation

AudioStream FilterTone::filter ( const AudioStream x)

Definition at line 63 of file FilterTone.cc.

References Nsound::Filter::filter().

Referenced by filter(), Nsound::Pluck::generate(), Nsound::GuitarBass::play(), and Nsound::FluteSlide::play().

64 {
65  return Filter::filter(x);
66 }
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
AudioStream FilterTone::filter ( const AudioStream x,
const Buffer hp_frequencies 
)

Definition at line 70 of file FilterTone.cc.

References Nsound::Filter::filter().

71 {
72  return Filter::filter(x, hp_frequencies);
73 }
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
Buffer FilterTone::filter ( const Buffer x)

Definition at line 77 of file FilterTone.cc.

References Nsound::Filter::filter().

78 {
79  return Filter::filter(x);
80 }
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
Buffer FilterTone::filter ( const Buffer x,
const Buffer hp_frequencies 
)

Definition at line 84 of file FilterTone.cc.

References Nsound::Filter::filter().

85 {
86  return Filter::filter(x, hp_frequencies);
87 }
AudioStream filter(const AudioStream &x)
Definition: Filter.cc:53
float64 FilterTone::filter ( const float64 x)
virtual

Implements Nsound::Filter.

Definition at line 91 of file FilterTone.cc.

References a_, b_, and last_output_.

92 {
93  float64 y = b_ * x - a_ * last_output_;
94 
95  last_output_ = y;
96 
97  return y;
98 }
double float64
Definition: Nsound.h:146
float64 last_output_
Definition: FilterTone.h:97
float64 FilterTone::filter ( const float64 x,
const float64 hp_frequency 
)
virtual

Implements Nsound::Filter.

Definition at line 102 of file FilterTone.cc.

References filter(), and makeKernel().

103 {
104  makeKernel(hp_frequency);
105 
106  return FilterTone::filter(x);
107 }
void makeKernel(const float64 &half_power_frequency)
Definition: FilterTone.cc:111
AudioStream filter(const AudioStream &x)
Definition: FilterTone.cc:63
float64 Nsound::FilterTone::getFrequency ( ) const
inline

Definition at line 76 of file FilterTone.h.

References hp_frequency_.

76 {return hp_frequency_;};
float64 hp_frequency_
Definition: FilterTone.h:94
uint32 Nsound::FilterTone::getKernelSize ( ) const
inlinevirtual

Reimplemented from Nsound::Filter.

Definition at line 79 of file FilterTone.h.

79 { return 2; };
void FilterTone::plot ( boolean  show_fc = true,
boolean  show_phase = false 
)

Definition at line 142 of file FilterTone.cc.

References Nsound::Plotter::axvline(), hp_frequency_, Nsound::Filter::plot(), Nsound::Filter::sample_rate_, Nsound::Plotter::subplot(), and Nsound::Plotter::title().

143 {
144  char title[128];
145  sprintf(title,
146  "Tone Filter Frequency Response\n"
147  "order = %d, fc = %0.1f Hz, sr = %0.1f Hz",
149 
150  Filter::plot(show_phase);
151 
152  Plotter pylab;
153 
154  uint32 n_rows = 1;
155 
156  if(show_phase)
157  {
158  n_rows = 2;
159  }
160 
161  if(show_fc)
162  {
163  pylab.subplot(n_rows, 1, 1);
164 
165  pylab.axvline(hp_frequency_,"color='red'");
166 
167  pylab.title(title);
168  }
169 
170 }
unsigned int uint32
Definition: Nsound.h:153
void axvline(const float64 &x_pos=0.0, const std::string &kwargs="")
Draws a vertical line at x and spans ymin to ymax (ralitive).
Definition: Plotter.cc:358
void title(const std::string &title, const std::string &kwargs="")
Add a title to the plot at the top and centered.
Definition: Plotter.cc:1127
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 plot(boolean show_phase=false)
Definition: Filter.cc:262
float64 hp_frequency_
Definition: FilterTone.h:94
float64 sample_rate_
Definition: Filter.h:113
void FilterTone::reset ( )
virtual

Resets interal history buffer and sets the cut off frequency to the one used at declaration.

Implements Nsound::Filter.

Definition at line 174 of file FilterTone.cc.

References hp_frequency_, last_output_, and makeKernel().

Referenced by FilterTone().

175 {
176  last_output_ = 0.0;
178 }
void makeKernel(const float64 &half_power_frequency)
Definition: FilterTone.cc:111
float64 last_output_
Definition: FilterTone.h:97
float64 hp_frequency_
Definition: FilterTone.h:94
void FilterTone::makeKernel ( const float64 half_power_frequency)

Definition at line 111 of file FilterTone.cc.

References a_, b_, kernel_cache_, and Nsound::Filter::two_pi_over_sample_rate_.

Referenced by filter(), and reset().

112 {
114  Kernel new_kernel(static_cast<uint32>(half_power_frequency * 10));
115 
116  // See if the kernel is in the cache.
117  KernelCache::const_iterator itor = kernel_cache_.find(new_kernel);
118 
119  if(itor != kernel_cache_.end())
120  {
121  // The kernel was found in the cache.
122  b_ = itor->b_;
123  a_ = itor->a_;
124  return;
125  }
126 
127  // The filter wasn't in the cache, need to make it.
128 
129  float64 temp = 2.0 - ::cos(two_pi_over_sample_rate_ * half_power_frequency);
130 
131  a_ = -1.0 * (temp - ::sqrt(temp * temp - 1.0));
132  b_ = 1.0 + a_;
133 
134  new_kernel.b_ = b_;
135  new_kernel.a_ = a_;
136 
137  kernel_cache_.insert(new_kernel);
138 }
double float64
Definition: Nsound.h:146
KernelCache kernel_cache_
Definition: FilterTone.h:114
A class to store calculated kernels.
Definition: FilterTone.h:100
float64 two_pi_over_sample_rate_
Definition: Filter.h:114
void Nsound::Filter::setRealtime ( bool  flag)
inlineinherited

Definition at line 57 of file Filter.h.

References Nsound::Filter::is_realtime_.

57 {is_realtime_ = flag;}
bool is_realtime_
Definition: Filter.h:118
AudioStream Filter::filter ( const AudioStream x,
const float64 frequency 
)
inherited

Definition at line 76 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::AudioStream::getNChannels(), Nsound::AudioStream::getSampleRate(), Nsound::Filter::is_realtime_, M_THROW, and Nsound::Filter::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
Buffer Filter::filter ( const Buffer x,
const float64 frequency 
)
inherited

Definition at line 140 of file Filter.cc.

References Nsound::Buffer::begin(), Nsound::Buffer::end(), Nsound::Filter::filter(), Nsound::Buffer::getLength(), Nsound::Filter::is_realtime_, and Nsound::Filter::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::getFrequencyAxis ( const uint32  n_fft = 8192)
inherited

Definition at line 185 of file Filter.cc.

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

Referenced by main(), Nsound::Filter::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)
inherited

Definition at line 210 of file Filter.cc.

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

Referenced by Nsound::FilterBandPassIIR::FilterBandPassIIR(), FilterLeastSquaresFIR_UnitTest(), Nsound::FilterIIR::getRMS(), main(), Nsound::Filter::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)
inherited

Definition at line 225 of file Filter.cc.

References Nsound::Filter::filter(), Nsound::Filter::is_realtime_, and Nsound::Filter::reset().

Referenced by Nsound::Filter::getFrequencyResponse(), Nsound::FilterHighPassFIR::getImpulseResponse(), Nsound::FilterLowPassFIR::getImpulseResponse(), Nsound::FilterLeastSquaresFIR::getImpulseResponse(), Nsound::FilterIIR::getImpulseResponse(), and Nsound::Filter::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
Buffer Filter::getPhaseResponse ( )
inherited

Definition at line 245 of file Filter.cc.

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

Referenced by Nsound::Filter::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
inlineinherited

Definition at line 102 of file Filter.h.

References Nsound::Filter::sample_rate_.

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

Definition at line 262 of file Filter.cc.

References Nsound::Plotter::figure(), Nsound::Buffer::getdB(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Buffer::getMax(), Nsound::Filter::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(), 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

Member Data Documentation

float64 Nsound::FilterTone::hp_frequency_
protected

Definition at line 94 of file FilterTone.h.

Referenced by getFrequency(), plot(), and reset().

float64 Nsound::FilterTone::b_
protected

Definition at line 95 of file FilterTone.h.

Referenced by filter(), and makeKernel().

float64 Nsound::FilterTone::a_
protected

Definition at line 96 of file FilterTone.h.

Referenced by filter(), and makeKernel().

float64 Nsound::FilterTone::last_output_
protected

Definition at line 97 of file FilterTone.h.

Referenced by filter(), and reset().

KernelCache Nsound::FilterTone::kernel_cache_
protected

Definition at line 114 of file FilterTone.h.

Referenced by makeKernel().

float64 Nsound::Filter::sample_rate_
protectedinherited

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(), Nsound::Filter::getFrequencyAxis(), Nsound::Filter::getFrequencyResponse(), Nsound::Filter::getPhaseResponse(), Nsound::Filter::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(), 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_
protectedinherited
float64 Nsound::Filter::sample_time_
protectedinherited

Definition at line 115 of file Filter.h.

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

uint32 Nsound::Filter::kernel_size_
protectedinherited
bool Nsound::Filter::is_realtime_
protectedinherited

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