sounds

package
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 Go to latest Published: Mar 15, 2020 License: GPL-3.0 Imports: 5 Imported by: 2

Documentation

Overview

Package sounds provides the basic types for Sounds within this system, plus multiple implementations of different sounds that can be used.

Index

Constants

View Source 
const (
	// CyclesPerSecond is the sample rate of each sound stream.
	CyclesPerSecond = 44100.0

	// SecondsPerCycle is the inverse sample rate.
	SecondsPerCycle = 1.0 / CyclesPerSecond

	// DurationPerCycle = int64(SecondsPerCycle * 1e9) * time.Nanosecond
	DurationPerCycle = 22675 * time.Nanosecond // BIG HACK

	// MaxLength represents the number of samples in the maximum duration.
	MaxLength = uint64(406750706825295)

	// MaxDuration is used for unending sounds.
	MaxDuration = time.Duration(int64(float64(MaxLength)*SecondsPerCycle*1e9)) * time.Nanosecond
)

Variables

This section is empty.

Functions

func DurationToSamples 

func DurationToSamples(duration time.Duration) uint64

DurationToSamples converts a duration of time to a sample count

func SamplesToDuration 

func SamplesToDuration(sampleCount uint64) time.Duration

SamplesToDuration converts a sample count to a duration of time.

func SawtoothMap 

func SawtoothMap(at float64) float64

func SineMap 

func SineMap(at float64) float64

Below are some sample mappers used for generating various useful shapes.

func SquareMap 

func SquareMap(at float64) float64

func TriangleMap 

func TriangleMap(at float64) float64

Types

type BaseSound 

type BaseSound struct {
	// contains filtered or unexported fields
}

A BaseSound manages state around the definition, and adapts all the Sound methods.

func (*BaseSound) Duration 

func (s *BaseSound) Duration() time.Duration

Duration returns the duration of time the sound runs for.

func (*BaseSound) GetSamples 

func (s *BaseSound) GetSamples() <-chan float64

GetSamples returns the samples for this sound, valid between a Start() and Stop()

func (*BaseSound) Length 

func (s *BaseSound) Length() uint64

Length returns the provided number of samples for this sound.

func (*BaseSound) Reset 

func (s *BaseSound) Reset()

Reset clears all the state in a stopped sound back to pre-Start values.

func (*BaseSound) Running 

func (s *BaseSound) Running() bool

Running returns whether Sound is still generating samples.

func (*BaseSound) Start 

func (s *BaseSound) Start()

Start begins the Sound by initialzing the channel, running the definition on a separate goroutine, and cleaning up once it has finished.

func (*BaseSound) Stop 

func (s *BaseSound) Stop()

Stop ends the sound, preventing any more samples from being written.

func (*BaseSound) String 

func (s *BaseSound) String() string

String returns the textual representation

func (*BaseSound) WriteSample 

func (s *BaseSound) WriteSample(sample float64) bool

WriteSample appends a sample to the channel, returning whether the write was successful.

type ChannelSound 

type ChannelSound struct {
	// contains filtered or unexported fields
}

A ChannelSound a sound of unknown length that is generated by a provided channel.

func (*ChannelSound) Duration 

func (s *ChannelSound) Duration() time.Duration

func (*ChannelSound) GetSamples 

func (s *ChannelSound) GetSamples() <-chan float64

func (*ChannelSound) Length 

func (s *ChannelSound) Length() uint64

func (*ChannelSound) Reset 

func (s *ChannelSound) Reset()

func (*ChannelSound) Running 

func (s *ChannelSound) Running() bool

func (*ChannelSound) Start 

func (s *ChannelSound) Start()

func (*ChannelSound) Stop 

func (s *ChannelSound) Stop()

func (*ChannelSound) String 

func (s *ChannelSound) String() string

type SimpleSampleMap 

type SimpleSampleMap func(float64) float64

type Sound 

type Sound interface {
	// Sound wave samples for the sound - only valid after Start() and before Stop()
	// NOTE: Only one sink should read from GetSamples(). Otherwise it will not receive every sample.
	GetSamples() <-chan float64

	// Number of samples in this sound, MaxLength if unlimited.
	Length() uint64

	// Length of time this goes for. Convenience method, should always be SamplesToDuration(Length())
	Duration() time.Duration

	// Start begins writing the sound wave to the samples channel.
	Start()

	// Running indicates whether a sound has Start()'d but not yet Stop()'d
	Running() bool

	// Stop ceases writing samples, and closes the channel.
	Stop()

	// Reset converts the sound back to the pre-Start() state. Can only be called on a Stop()'d Sound.
	Reset()
}

A Sound is a model of a physical sound wave as a series of pressure changes over time.

Each Sound contains a channel of samples in the range [-1, 1] of the intensity at each time step, as well as a count of samples, which then also defines how long the sound lasts.

Sounds also provide a way to start and stop when the samples are written, and reset to an initial state.

func AddDelay 

func AddDelay(wrapped Sound, delayMs float64) Sound

AddDelay takes a sound, and adds it with a delayed version of itself after a given duration.

For example, to have a three note progression with a delay of 123ms: 

s.AddDelay(s.ConcatSounds(
  s.NewTimedSound(u.MidiToSound(55), 678),
  s.NewTimedSound(u.MidiToSound(59), 678),
  s.NewTimedSound(u.MidiToSound(62), 678),
), 123)

func ConcatSounds 

func ConcatSounds(wrapped ...Sound) Sound

ConcatSounds creates a sound by concatenating multiple sounds in series.

For example, to create the 5-note sequence from Close Enounters: 

s := sounds.ConcatSounds(
	sounds.NewTimedSound(sounds.MidiToSound(74), 400),
	sounds.NewTimedSound(sounds.MidiToSound(76), 400),
	sounds.NewTimedSound(sounds.MidiToSound(72), 400),
	sounds.NewTimedSound(sounds.MidiToSound(60), 400),
	sounds.NewTimedSound(sounds.MidiToSound(67), 1200),
)

func LinearSample 

func LinearSample(wrapped Sound, pitchScale float64) Sound

LinearSample wraps an existing sound and samples it at a different rate, modifying both its pitch and duration.

For example, to modulate a sound up an octave, and make it half as long: 

s := ...some sound...
higher := sounds.LinearSample(s, 2.0)

func MultiplyWithClip 

func MultiplyWithClip(wrapped Sound, factor float64) Sound

MultiplyWithClip wraps an existing sound and scales its amplitude by a given factory, clipping the result to [-1, 1].

For example, to create a sound half as loud as the default E5 sine wave: 

s := sounds.MultiplyWithClip(sounds.NewSineWave(659.25), 0.5)

func NewADSREnvelope 

func NewADSREnvelope(wrapped Sound,
	attackMs float64, delayMs float64, sustainLevel float64, releaseMs float64) Sound

NewADSREnvelope wraps an existing sound with a parametric envelope.

For details, read https://en.wikipedia.org/wiki/Synthesizer#ADSR_envelope

For example, to create an envelope around an A440 note 

s := sounds.NewADSREnvelope(
	sounds.NewTimedSound(sounds.NewSineWave(261.63), 1000),
	50, 200, 0.5, 100)

func NewBaseSound 

func NewBaseSound(def SoundDefinition, sampleCount uint64) Sound

NewBaseSound takes a simpler definition of a sound, plus a duration, and converts them into something that implements the Sound interface.

func NewDenseIIR 

func NewDenseIIR(wrapped Sound, inCoef []float64, outCoef []float64) Sound

NewDenseIIR wrapps a sound in an IIR filter, as specified by the coefficients. TODO(padster): Also implement the filter design algorithms, e.g: 

http://engineerjs.com/?sidebar=docs/iir.html
http://www.mikroe.com/chapters/view/73/chapter-3-iir-filters/
http://www-users.cs.york.ac.uk/~fisher/mkfilter/

For example, to use a high-pass filter for 800hz+ with sample rate of 44.1k: 

sound := s.NewDenseIIR(...some sound...,
  []float64{0.8922, -2.677, 2.677, -0.8922},
  []float64{2.772, -2.57, 0.7961},
)

func NewHzFromChannel 

func NewHzFromChannel(wrapped <-chan float64) Sound

NewHzFromChannel takes stream of hz values, and generates a tone that sounds like those values over time. For a fixed tone, see NewSineWave.

func NewHzFromChannelWithAmplitude 

func NewHzFromChannelWithAmplitude(wrappedWithAmplitute <-chan []float64) Sound

func NewKarplusStrong 

func NewKarplusStrong(hz float64, sustain float64) Sound

NewKarplusStrong creates a note at a given frequency by starting with white noise then feeding that back into itself with a delay, which ends up sounding like a string. See http://music.columbia.edu/cmc/MusicAndComputers/chapter4/04_09.php

For example, to create a string sound at 440hz that never gets quieter: 

stringA := sounds.NewKarplusStrong(440.0, 1.0)

func NewSawtoothWave 

func NewSawtoothWave(hz float64) Sound

NewSawtoothWave creates an unending sawtooth pattern (-1->1 then resets to -1.)

func NewSilence 

func NewSilence() Sound

NewSilence creates an unending sound that is inaudible.

func NewSimpleWave 

func NewSimpleWave(hz float64, mapper SimpleSampleMap) Sound

NewSimpleWave creates an unending repeating sound based on cycles defined by a given mapping function. For examples of usage, see sine/square/sawtooth/triangle waves below.

func NewSineWave 

func NewSineWave(hz float64) Sound

NewSineWave creates an unending sinusoid at a given pitch (in hz).

For example, to create a sound represeting A440: 

s := sounds.NewSineWave(440)

func NewSquareWave 

func NewSquareWave(hz float64) Sound

NewSquareWave creates an unending [-1, 1] square wave at a given pitch.

func NewTimedSilence 

func NewTimedSilence(durationMs float64) Sound

NewTimedSilence creates a silence that lasts for a given duration.

For example, Cage's 4'33" can be generated using: 

s := sounds.NewTimedSilence(273000)

func NewTimedSound 

func NewTimedSound(wrapped Sound, durationMs float64) Sound

NewSilence wraps an existing sound as something that stops after a given duration.

For example, to create a sound of middle C that lasts a second: 

s := sounds.NewTimedSound(sounds.NewSineWave(261.63), 1000)

func NewTriangleWave 

func NewTriangleWave(hz float64) Sound

NewTriangleWave creates an unending triangle pattern (-1->1->-1 linearly)

func RepeatSound 

func RepeatSound(wrapped Sound, loopCount int32) Sound

RepeatSound forms a sound by repeating a given sound a number of times in series.

For example, for the cello part of Pachelbel's Canon in D: 

sound := s.RepeatSound(s.ConcatSounds(
	s.NewTimedSound(s.MidiToSound(50), 800),
	s.NewTimedSound(s.MidiToSound(45), 800),
	s.NewTimedSound(s.MidiToSound(47), 800),
	s.NewTimedSound(s.MidiToSound(42), 800),
	s.NewTimedSound(s.MidiToSound(43), 800),
	s.NewTimedSound(s.MidiToSound(38), 800),
	s.NewTimedSound(s.MidiToSound(43), 800),
	s.NewTimedSound(s.MidiToSound(45), 800),
), -1 /* repeat indefinitely */)

func SumSounds 

func SumSounds(wrapped ...Sound) Sound

SumSounds creates a sound by adding multiple sounds in parallel, playing them at the same time and normalizing their volume.

For example, to play a G7 chord for a second: 

s := sounds.SumSounds(
	sounds.NewTimedSound(sounds.MidiToSound(55), 1000),
	sounds.NewTimedSound(sounds.MidiToSound(59), 1000),
	sounds.NewTimedSound(sounds.MidiToSound(62), 1000),
	sounds.NewTimedSound(sounds.MidiToSound(65), 1000),
	sounds.NewTimedSound(sounds.MidiToSound(67), 1000),
)

func WrapChannelAsSound 

func WrapChannelAsSound(samples <-chan float64) Sound

WrapChannelAsSound takes an input sample channel and adapts it to be a Sound.

For example, to play a sample channel: 

output.Play(sounds.WrapChannelAsSound(..samples..))

func WrapSliceAsSound 

func WrapSliceAsSound(samples []float64) Sound

WrapSliceAsSound wraps an already created slice of [-1, 1] as a sound.

type SoundDefinition 

type SoundDefinition interface {
	// Run executes the normal logic of the sound, writing to base.WriteSample until it is false.
	Run(base *BaseSound)

	// Stop cleans up at the end of the Sound.
	Stop()

	// Reset rewrites all state to the same as before Run()
	Reset()
}

A SoundDefinition represents the simplified requirements that BaseSound converts into a Sound. If possible it is recommended that implementations be immutable, with all mutable state within Run().

Source Files

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