Backbone::SingerToneDSP Class Reference

Pitch-related DSP utilities and coarse-to-fine pitch detection. More...

Public Member Functions
	SingerToneDSP (double sampleRate, float minPitch, float maxPitch, float detectLevelThreshold)
	Initializes the DSP with sampling parameters and detection limits.
float	DetectPitch (float[] samplesLo, float[] samplesHi, int numSamples)
	Detects pitch on a frame using low/high prefiltered signals and a level gate.
bool	LevelIsAbove (float[] buffer, int len, float level)
	Returns true if any sample within the first len entries has absolute value at least level .
float	MidiNoteToPitch (float note)
	Converts a floating MIDI note to pitch in Hz (limited by m_maxPitch).

Static Public Member Functions
static double	CreateSineWave (float[] buffer, int numSamples, float sampleRate, float freq, float amplitude, double startAngle)
	Fills buffer with a sine wave. Returns the updated phase.
static void	CopyBuffer (T[] source, int srcStart, T[] destination, int dstStart, int length)
	Copies a block of elements from source to destination .
static bool	PitchToMidiNote (float pitch, out int note, out int cents)
	Converts a pitch in Hz to integer MIDI note and cents.
static float	PitchToMidiNote (float pitch)
	Converts a pitch in Hz to floating MIDI note (note + cents/100).
static string	GetNoteName (int note, bool sharps, bool showOctave)
	Formats a MIDI note to its musical note name.

Public Attributes
float	MaxPitch => m_maxPitch
	Maximum detectable pitch (Hz).
float	MinPitch => m_minPitch
	Minimum detectable pitch (Hz).
int	MaxNote => m_maxNote
	Maximum MIDI note supported.
int	MinNote => m_minNote
	Minimum MIDI note supported.

Static Public Attributes
static readonly double	InvLn2 = 1.0 / Math.Log(2.0)
	1 / ln(2). Used to convert natural logarithms to log2.

Private Member Functions
int	CourseIndexForFreq (float hz)
	Returns coarse index for a given frequency in Hz.
float	DetectPitchLo (float[] samplesLo, float[] samplesHi)
	Coarse pass: scans candidate periods and refines around peaks.
float	DetectPitchHi (float[] samples, int lowFreqIdx)
	High-resolution refinement around the best coarse candidate.
float	InterpolateHermite (float fY0, float fY1, float fY2, float fY3, float frac)
	4-point, 3rd-order Hermite interpolation.
float	InterpolateLinear (float y0, float y1, float frac)
	Linear interpolation.
float	RatioAbsDiffLinear (float[] samples, int freqIdx, int blockLen, int stepSize, bool hiRes)
	Medium/low resolution ratio of absolute differences using linear interpolation.
float	SumAbsDiffHermite (float[] samples, float fOffset, int blockLen, int stepSize)
	Medium/high resolution sum of absolute differences using Hermite interpolation.

Private Attributes
const int	kCourseOctaveSteps = 96
const int	kScanHiSize = 31
const float	kScanHiFreqStep = 1.005f
const int	kMinMidiNote = 21
const int	kMaxMidiNote = 108
const int	kSkipSize = 8
const int	kPeakScanSize = 23
const float	kPeakThresh1 = 200f
const float	kPeakThresh2 = 600f
const int	kHiResDeltaIdx = 5
const int	kLoResDivisor = 10
const int	kHiResStepMin = 1
const int	kHiResStepMax = 5
const float	kPointyNear = 1.2f
const float	kPointyFar = 1.5f
const float	kLoHiSwitchFreqHz = 250f
float	m_minPitch
float	m_maxPitch
int	m_minNote
int	m_maxNote
int	m_blockLen14
int	m_blockLen24
int	m_blockLen34
int	m_blockLen44
double	m_sampleRate
float	m_detectLevelThreshold
int	m_numCourseSteps
float[]	m_pCourseFreqOffset
float[]	m_pCourseFreq
readonly float[]	m_scanHiOffset = new float[kScanHiSize]
readonly float[]	m_peakBuf = new float[kScanHiSize]
int	m_prevPitchIdx
float[]	m_detectCurve

Detailed Description

Pitch-related DSP utilities and coarse-to-fine pitch detection.

Constructor & Destructor Documentation

SingerToneDSP()

Backbone::SingerToneDSP::SingerToneDSP	(	double	sampleRate,
		float	minPitch,
		float	maxPitch,
		float	detectLevelThreshold )

Initializes the DSP with sampling parameters and detection limits.

Parameters

sampleRate	Sampling rate in Hz.
minPitch	Minimum detectable pitch in Hz.
maxPitch	Maximum detectable pitch in Hz.
detectLevelThreshold	Absolute signal threshold to attempt detection.

Member Function Documentation

CopyBuffer()

static void Backbone::SingerToneDSP::CopyBuffer ( T[] source, int srcStart, T[] destination, int dstStart, int length )

static

Copies a block of elements from source to destination .

Exceptions

ArgumentOutOfRangeException	If length is negative.
Exception	If source or destination buffers are too small.

CourseIndexForFreq()

int Backbone::SingerToneDSP::CourseIndexForFreq ( float hz )

private

Returns coarse index for a given frequency in Hz.

CreateSineWave()

static double Backbone::SingerToneDSP::CreateSineWave ( float[] buffer, int numSamples, float sampleRate, float freq, float amplitude, double startAngle )

static

Fills buffer with a sine wave. Returns the updated phase.

DetectPitch()

float Backbone::SingerToneDSP::DetectPitch	(	float[]	samplesLo,
		float[]	samplesHi,
		int	numSamples )

Detects pitch on a frame using low/high prefiltered signals and a level gate.

Parameters

samplesLo	Low-band samples.
samplesHi	High-band samples.
numSamples	Number of valid samples in the arrays.

Returns

Detected pitch in Hz, or 0 if not found.

DetectPitchHi()

float Backbone::SingerToneDSP::DetectPitchHi ( float[] samples, int lowFreqIdx )

private

High-resolution refinement around the best coarse candidate.

DetectPitchLo()

float Backbone::SingerToneDSP::DetectPitchLo ( float[] samplesLo, float[] samplesHi )

private

Coarse pass: scans candidate periods and refines around peaks.

GetNoteName()

static string Backbone::SingerToneDSP::GetNoteName ( int note, bool sharps, bool showOctave )

static

Formats a MIDI note to its musical note name.

Parameters

note	MIDI note number.
sharps	If true uses sharps, otherwise flats.
showOctave	If true appends the octave number.

Returns

Formatted name or null if out of supported range.

InterpolateHermite()

float Backbone::SingerToneDSP::InterpolateHermite ( float fY0, float fY1, float fY2, float fY3, float frac )

private

4-point, 3rd-order Hermite interpolation.

InterpolateLinear()

float Backbone::SingerToneDSP::InterpolateLinear ( float y0, float y1, float frac )

private

Linear interpolation.

LevelIsAbove()

bool Backbone::SingerToneDSP::LevelIsAbove	(	float[]	buffer,
		int	len,
		float	level )

Returns true if any sample within the first len entries has absolute value at least level .

MidiNoteToPitch()

float Backbone::SingerToneDSP::MidiNoteToPitch

(

float

note

)

Converts a floating MIDI note to pitch in Hz (limited by m_maxPitch).

PitchToMidiNote() [1/2]

static float Backbone::SingerToneDSP::PitchToMidiNote ( float pitch )

static

Converts a pitch in Hz to floating MIDI note (note + cents/100).

PitchToMidiNote() [2/2]

static bool Backbone::SingerToneDSP::PitchToMidiNote ( float pitch, out int note, out int cents )

static

Converts a pitch in Hz to integer MIDI note and cents.

RatioAbsDiffLinear()

float Backbone::SingerToneDSP::RatioAbsDiffLinear ( float[] samples, int freqIdx, int blockLen, int stepSize, bool hiRes )

private

Medium/low resolution ratio of absolute differences using linear interpolation.

SumAbsDiffHermite()

float Backbone::SingerToneDSP::SumAbsDiffHermite ( float[] samples, float fOffset, int blockLen, int stepSize )

private

Medium/high resolution sum of absolute differences using Hermite interpolation.

Member Data Documentation

InvLn2

readonly double Backbone::SingerToneDSP::InvLn2 = 1.0 / Math.Log(2.0)

static

1 / ln(2). Used to convert natural logarithms to log2.

kCourseOctaveSteps

const int Backbone::SingerToneDSP::kCourseOctaveSteps = 96

private

kHiResDeltaIdx

const int Backbone::SingerToneDSP::kHiResDeltaIdx = 5

private

kHiResStepMax

const int Backbone::SingerToneDSP::kHiResStepMax = 5

private

kHiResStepMin

const int Backbone::SingerToneDSP::kHiResStepMin = 1

private

kLoHiSwitchFreqHz

const float Backbone::SingerToneDSP::kLoHiSwitchFreqHz = 250f

private

kLoResDivisor

const int Backbone::SingerToneDSP::kLoResDivisor = 10

private

kMaxMidiNote

const int Backbone::SingerToneDSP::kMaxMidiNote = 108

private

kMinMidiNote

const int Backbone::SingerToneDSP::kMinMidiNote = 21

private

kPeakScanSize

const int Backbone::SingerToneDSP::kPeakScanSize = 23

private

kPeakThresh1

const float Backbone::SingerToneDSP::kPeakThresh1 = 200f

private

kPeakThresh2

const float Backbone::SingerToneDSP::kPeakThresh2 = 600f

private

kPointyFar

const float Backbone::SingerToneDSP::kPointyFar = 1.5f

private

kPointyNear

const float Backbone::SingerToneDSP::kPointyNear = 1.2f

private

kScanHiFreqStep

const float Backbone::SingerToneDSP::kScanHiFreqStep = 1.005f

private

kScanHiSize

const int Backbone::SingerToneDSP::kScanHiSize = 31

private

kSkipSize

const int Backbone::SingerToneDSP::kSkipSize = 8

private

m_blockLen14

int Backbone::SingerToneDSP::m_blockLen14

private

m_blockLen24

int Backbone::SingerToneDSP::m_blockLen24

private

m_blockLen34

int Backbone::SingerToneDSP::m_blockLen34

private

m_blockLen44

int Backbone::SingerToneDSP::m_blockLen44

private

m_detectCurve

float [] Backbone::SingerToneDSP::m_detectCurve

private

m_detectLevelThreshold

float Backbone::SingerToneDSP::m_detectLevelThreshold

private

m_maxNote

int Backbone::SingerToneDSP::m_maxNote

private

m_maxPitch

float Backbone::SingerToneDSP::m_maxPitch

private

m_minNote

int Backbone::SingerToneDSP::m_minNote

private

m_minPitch

float Backbone::SingerToneDSP::m_minPitch

private

m_numCourseSteps

int Backbone::SingerToneDSP::m_numCourseSteps

private

m_pCourseFreq

float [] Backbone::SingerToneDSP::m_pCourseFreq

private

m_pCourseFreqOffset

float [] Backbone::SingerToneDSP::m_pCourseFreqOffset

private

m_peakBuf

readonly float [] Backbone::SingerToneDSP::m_peakBuf = new float[kScanHiSize]

private

m_prevPitchIdx

int Backbone::SingerToneDSP::m_prevPitchIdx

private

m_sampleRate

double Backbone::SingerToneDSP::m_sampleRate

private

m_scanHiOffset

readonly float [] Backbone::SingerToneDSP::m_scanHiOffset = new float[kScanHiSize]

private

MaxNote

int Backbone::SingerToneDSP::MaxNote => m_maxNote

Maximum MIDI note supported.

MaxPitch

float Backbone::SingerToneDSP::MaxPitch => m_maxPitch

Maximum detectable pitch (Hz).

MinNote

int Backbone::SingerToneDSP::MinNote => m_minNote

Minimum MIDI note supported.

MinPitch

float Backbone::SingerToneDSP::MinPitch => m_minPitch

Minimum detectable pitch (Hz).

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

• D:/Unity/Backbone/Assets/Backbone/Singer Tone/Scripts/Core/SingerToneDSP.cs