feat: add advanced audio effects and improve UI

Phase 6.5 Advanced Effects:
- Add Pitch Shifter with semitones and cents adjustment
- Add Time Stretch with pitch preservation using overlap-add
- Add Distortion with soft/hard/tube types and tone control
- Add Bitcrusher with bit depth and sample rate reduction
- Add AdvancedParameterDialog with real-time waveform visualization
- Add 4 professional presets per effect type

Improvements:
- Fix undefined parameter errors by adding nullish coalescing operators
- Add global custom scrollbar styling with color-mix transparency
- Add custom-scrollbar utility class for side panel
- Improve theme-aware scrollbar appearance in light/dark modes
- Fix parameter initialization when switching effect types

Integration:
- All advanced effects support undo/redo via EffectCommand
- Effects accessible via command palette and side panel
- Selection-based processing support
- Toast notifications for all effects

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
2025-11-17 20:03:40 +01:00
parent f414573655
commit ee48f9475f
26 changed files with 6027 additions and 273 deletions

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/**
* Advanced effects (Pitch Shifter, Time Stretcher, Distortion, Bitcrusher)
*/
import { getAudioContext } from '../context';
export interface PitchShifterParameters {
semitones: number; // -12 to +12 - pitch shift in semitones
cents: number; // -100 to +100 - fine tuning in cents
mix: number; // 0-1 - dry/wet mix
}
export interface TimeStretchParameters {
rate: number; // 0.5-2.0 - playback rate (0.5 = half speed, 2 = double speed)
preservePitch: boolean; // whether to preserve pitch
mix: number; // 0-1 - dry/wet mix
}
export interface DistortionParameters {
drive: number; // 0-1 - amount of distortion
tone: number; // 0-1 - pre-distortion tone control
output: number; // 0-1 - output level
type: 'soft' | 'hard' | 'tube'; // distortion type
mix: number; // 0-1 - dry/wet mix
}
export interface BitcrusherParameters {
bitDepth: number; // 1-16 - bit depth
sampleRate: number; // 100-48000 - sample rate reduction
mix: number; // 0-1 - dry/wet mix
}
/**
* Apply pitch shifting to audio buffer
* Uses simple time-domain pitch shifting (overlap-add)
*/
export async function applyPitchShift(
buffer: AudioBuffer,
params: PitchShifterParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const sampleRate = buffer.sampleRate;
// Calculate pitch shift ratio
const totalCents = params.semitones * 100 + params.cents;
const pitchRatio = Math.pow(2, totalCents / 1200);
// For pitch shifting, we change the playback rate then resample
const newLength = Math.floor(buffer.length / pitchRatio);
const outputBuffer = audioContext.createBuffer(channels, newLength, sampleRate);
// Simple linear interpolation resampling
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < newLength; i++) {
const srcIndex = i * pitchRatio;
const srcIndexInt = Math.floor(srcIndex);
const srcIndexFrac = srcIndex - srcIndexInt;
if (srcIndexInt < buffer.length - 1) {
const sample1 = inputData[srcIndexInt];
const sample2 = inputData[srcIndexInt + 1];
const interpolated = sample1 + (sample2 - sample1) * srcIndexFrac;
// Mix dry/wet
const dry = i < buffer.length ? inputData[i] : 0;
outputData[i] = dry * (1 - params.mix) + interpolated * params.mix;
} else if (srcIndexInt < buffer.length) {
const dry = i < buffer.length ? inputData[i] : 0;
outputData[i] = dry * (1 - params.mix) + inputData[srcIndexInt] * params.mix;
}
}
}
return outputBuffer;
}
/**
* Apply time stretching to audio buffer
* Changes duration without affecting pitch (basic implementation)
*/
export async function applyTimeStretch(
buffer: AudioBuffer,
params: TimeStretchParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const sampleRate = buffer.sampleRate;
if (params.preservePitch) {
// Time stretch with pitch preservation (overlap-add)
const newLength = Math.floor(buffer.length / params.rate);
const outputBuffer = audioContext.createBuffer(channels, newLength, sampleRate);
const windowSize = 2048;
const hopSize = Math.floor(windowSize / 4);
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
let readPos = 0;
let writePos = 0;
while (writePos < newLength) {
// Simple overlap-add
for (let i = 0; i < windowSize && writePos + i < newLength; i++) {
const readIndex = Math.floor(readPos + i);
if (readIndex < buffer.length) {
// Hanning window
const window = 0.5 * (1 - Math.cos((2 * Math.PI * i) / windowSize));
outputData[writePos + i] += inputData[readIndex] * window;
}
}
readPos += hopSize * params.rate;
writePos += hopSize;
}
// Normalize
let maxVal = 0;
for (let i = 0; i < newLength; i++) {
maxVal = Math.max(maxVal, Math.abs(outputData[i]));
}
if (maxVal > 0) {
for (let i = 0; i < newLength; i++) {
outputData[i] /= maxVal;
}
}
}
return outputBuffer;
} else {
// Simple speed change (changes pitch)
const newLength = Math.floor(buffer.length / params.rate);
const outputBuffer = audioContext.createBuffer(channels, newLength, sampleRate);
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < newLength; i++) {
const srcIndex = i * params.rate;
const srcIndexInt = Math.floor(srcIndex);
const srcIndexFrac = srcIndex - srcIndexInt;
if (srcIndexInt < buffer.length - 1) {
const sample1 = inputData[srcIndexInt];
const sample2 = inputData[srcIndexInt + 1];
outputData[i] = sample1 + (sample2 - sample1) * srcIndexFrac;
} else if (srcIndexInt < buffer.length) {
outputData[i] = inputData[srcIndexInt];
}
}
}
return outputBuffer;
}
}
/**
* Apply distortion/overdrive effect
*/
export async function applyDistortion(
buffer: AudioBuffer,
params: DistortionParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Distortion function based on type
const distort = (sample: number, drive: number, type: string): number => {
const x = sample * (1 + drive * 10);
switch (type) {
case 'soft':
// Soft clipping (tanh)
return Math.tanh(x);
case 'hard':
// Hard clipping
return Math.max(-1, Math.min(1, x));
case 'tube':
// Tube-like distortion (asymmetric)
if (x > 0) {
return 1 - Math.exp(-x);
} else {
return -1 + Math.exp(x);
}
default:
return x;
}
};
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
// Simple low-pass filter for tone control
let filterState = 0;
const filterCutoff = params.tone;
for (let i = 0; i < length; i++) {
let sample = inputData[i];
// Pre-distortion tone filter
filterState = filterState * (1 - filterCutoff) + sample * filterCutoff;
sample = filterState;
// Apply distortion
const distorted = distort(sample, params.drive, params.type);
// Output level
const processed = distorted * params.output;
// Mix dry/wet
outputData[i] = inputData[i] * (1 - params.mix) + processed * params.mix;
}
}
return outputBuffer;
}
/**
* Apply bitcrusher effect
*/
export async function applyBitcrusher(
buffer: AudioBuffer,
params: BitcrusherParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Calculate bit depth quantization step
const bitLevels = Math.pow(2, params.bitDepth);
const step = 2 / bitLevels;
// Calculate sample rate reduction ratio
const srRatio = sampleRate / params.sampleRate;
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
let holdSample = 0;
let holdCounter = 0;
for (let i = 0; i < length; i++) {
// Sample rate reduction (sample and hold)
if (holdCounter <= 0) {
let sample = inputData[i];
// Bit depth reduction
sample = Math.floor(sample / step) * step;
holdSample = sample;
holdCounter = srRatio;
}
holdCounter--;
// Mix dry/wet
outputData[i] = inputData[i] * (1 - params.mix) + holdSample * params.mix;
}
}
return outputBuffer;
}

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/**
* Dynamics processing effects (Compressor, Limiter, Gate/Expander)
*/
import { getAudioContext } from '../context';
export interface CompressorParameters {
threshold: number; // dB - level where compression starts
ratio: number; // Compression ratio (e.g., 4 = 4:1)
attack: number; // ms - how quickly to compress
release: number; // ms - how quickly to stop compressing
knee: number; // dB - width of soft knee (0 = hard knee)
makeupGain: number; // dB - gain to apply after compression
}
export interface LimiterParameters {
threshold: number; // dB - maximum level
attack: number; // ms - how quickly to limit
release: number; // ms - how quickly to stop limiting
makeupGain: number; // dB - gain to apply after limiting
}
export interface GateParameters {
threshold: number; // dB - level below which gate activates
ratio: number; // Expansion ratio (e.g., 2 = 2:1)
attack: number; // ms - how quickly to close gate
release: number; // ms - how quickly to open gate
knee: number; // dB - width of soft knee
}
/**
* Apply compression to audio buffer
*/
export async function applyCompressor(
buffer: AudioBuffer,
params: CompressorParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Create output buffer
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Convert time constants to samples
const attackSamples = (params.attack / 1000) * sampleRate;
const releaseSamples = (params.release / 1000) * sampleRate;
// Convert dB to linear
const thresholdLinear = dbToLinear(params.threshold);
const makeupGainLinear = dbToLinear(params.makeupGain);
const kneeLinear = dbToLinear(params.knee);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
let envelope = 0;
for (let i = 0; i < length; i++) {
const input = inputData[i];
const inputAbs = Math.abs(input);
// Envelope follower with attack/release
if (inputAbs > envelope) {
envelope = envelope + (inputAbs - envelope) / attackSamples;
} else {
envelope = envelope + (inputAbs - envelope) / releaseSamples;
}
// Calculate gain reduction
let gain = 1.0;
if (envelope > thresholdLinear) {
// Soft knee calculation
const overThreshold = envelope - thresholdLinear;
const kneeRange = kneeLinear / 2;
if (params.knee > 0 && overThreshold < kneeRange) {
// In the knee region - smooth transition
const kneeRatio = overThreshold / kneeRange;
const compressionAmount = (1 - 1 / params.ratio) * kneeRatio;
gain = 1 - compressionAmount * (overThreshold / envelope);
} else {
// Above knee - full compression
const exceededDb = linearToDb(envelope) - params.threshold;
const gainReductionDb = exceededDb * (1 - 1 / params.ratio);
gain = dbToLinear(-gainReductionDb);
}
}
// Apply gain reduction and makeup gain
outputData[i] = input * gain * makeupGainLinear;
}
}
return outputBuffer;
}
/**
* Apply limiting to audio buffer
*/
export async function applyLimiter(
buffer: AudioBuffer,
params: LimiterParameters
): Promise<AudioBuffer> {
// Limiter is essentially a compressor with infinite ratio
return applyCompressor(buffer, {
threshold: params.threshold,
ratio: 100, // Very high ratio approximates infinity:1
attack: params.attack,
release: params.release,
knee: 0, // Hard knee for brick-wall limiting
makeupGain: params.makeupGain,
});
}
/**
* Apply gate/expander to audio buffer
*/
export async function applyGate(
buffer: AudioBuffer,
params: GateParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Create output buffer
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Convert time constants to samples
const attackSamples = (params.attack / 1000) * sampleRate;
const releaseSamples = (params.release / 1000) * sampleRate;
// Convert dB to linear
const thresholdLinear = dbToLinear(params.threshold);
const kneeLinear = dbToLinear(params.knee);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
let envelope = 0;
for (let i = 0; i < length; i++) {
const input = inputData[i];
const inputAbs = Math.abs(input);
// Envelope follower with attack/release
if (inputAbs > envelope) {
envelope = envelope + (inputAbs - envelope) / attackSamples;
} else {
envelope = envelope + (inputAbs - envelope) / releaseSamples;
}
// Calculate gain reduction
let gain = 1.0;
if (envelope < thresholdLinear) {
// Below threshold - apply expansion/gating
const belowThreshold = thresholdLinear - envelope;
const kneeRange = kneeLinear / 2;
if (params.knee > 0 && belowThreshold < kneeRange) {
// In the knee region - smooth transition
const kneeRatio = belowThreshold / kneeRange;
const expansionAmount = (1 - params.ratio) * kneeRatio;
gain = 1 + expansionAmount * (belowThreshold / thresholdLinear);
} else {
// Below knee - full expansion
const belowDb = params.threshold - linearToDb(envelope);
const gainReductionDb = belowDb * (params.ratio - 1);
gain = dbToLinear(-gainReductionDb);
}
// Clamp to prevent extreme amplification
gain = Math.max(0, Math.min(1, gain));
}
// Apply gain
outputData[i] = input * gain;
}
}
return outputBuffer;
}
/**
* Convert decibels to linear gain
*/
function dbToLinear(db: number): number {
return Math.pow(10, db / 20);
}
/**
* Convert linear gain to decibels
*/
function linearToDb(linear: number): number {
return 20 * Math.log10(Math.max(linear, 0.00001)); // Prevent log(0)
}

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/**
* Fade in/out effects
*/
import { getAudioContext } from '../context';
export type FadeType = 'linear' | 'exponential' | 'logarithmic';
/**
* Apply fade in to audio buffer
* @param buffer - Source audio buffer
* @param duration - Fade duration in seconds
* @param type - Fade curve type
* @returns New audio buffer with fade in applied
*/
export function applyFadeIn(
buffer: AudioBuffer,
duration: number,
type: FadeType = 'linear'
): AudioBuffer {
const audioContext = getAudioContext();
const fadeSamples = Math.min(
Math.floor(duration * buffer.sampleRate),
buffer.length
);
const outputBuffer = audioContext.createBuffer(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
if (i < fadeSamples) {
const progress = i / fadeSamples;
const gain = calculateFadeGain(progress, type);
outputData[i] = inputData[i] * gain;
} else {
outputData[i] = inputData[i];
}
}
}
return outputBuffer;
}
/**
* Apply fade out to audio buffer
* @param buffer - Source audio buffer
* @param duration - Fade duration in seconds
* @param type - Fade curve type
* @returns New audio buffer with fade out applied
*/
export function applyFadeOut(
buffer: AudioBuffer,
duration: number,
type: FadeType = 'linear'
): AudioBuffer {
const audioContext = getAudioContext();
const fadeSamples = Math.min(
Math.floor(duration * buffer.sampleRate),
buffer.length
);
const fadeStartSample = buffer.length - fadeSamples;
const outputBuffer = audioContext.createBuffer(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
if (i >= fadeStartSample) {
const progress = (i - fadeStartSample) / fadeSamples;
const gain = calculateFadeGain(1 - progress, type);
outputData[i] = inputData[i] * gain;
} else {
outputData[i] = inputData[i];
}
}
}
return outputBuffer;
}
/**
* Calculate fade gain based on progress and curve type
* @param progress - Progress from 0 to 1
* @param type - Fade curve type
* @returns Gain value from 0 to 1
*/
function calculateFadeGain(progress: number, type: FadeType): number {
switch (type) {
case 'linear':
return progress;
case 'exponential':
// Exponential curve: faster at the start, slower at the end
return progress * progress;
case 'logarithmic':
// Logarithmic curve: slower at the start, faster at the end
return Math.sqrt(progress);
default:
return progress;
}
}

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/**
* Audio filter effects using BiquadFilterNode
*/
import { getAudioContext } from '../context';
export type FilterType = 'lowpass' | 'highpass' | 'bandpass' | 'lowshelf' | 'highshelf' | 'peaking' | 'notch' | 'allpass';
export interface FilterOptions {
type: FilterType;
frequency: number;
Q?: number;
gain?: number;
}
/**
* Apply a filter to an audio buffer using offline audio processing
* @param buffer - Source audio buffer
* @param options - Filter options
* @returns New audio buffer with filter applied
*/
export async function applyFilter(
buffer: AudioBuffer,
options: FilterOptions
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
// Create offline context for processing
const offlineContext = new OfflineAudioContext(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
// Create source from buffer
const source = offlineContext.createBufferSource();
source.buffer = buffer;
// Create and configure filter
const filter = offlineContext.createBiquadFilter();
filter.type = options.type;
filter.frequency.setValueAtTime(options.frequency, offlineContext.currentTime);
if (options.Q !== undefined) {
filter.Q.setValueAtTime(options.Q, offlineContext.currentTime);
}
if (options.gain !== undefined) {
filter.gain.setValueAtTime(options.gain, offlineContext.currentTime);
}
// Connect nodes
source.connect(filter);
filter.connect(offlineContext.destination);
// Start playback and render
source.start(0);
const renderedBuffer = await offlineContext.startRendering();
return renderedBuffer;
}
/**
* Apply low-pass filter (cuts high frequencies)
* @param buffer - Source audio buffer
* @param frequency - Cutoff frequency in Hz (default: 1000)
* @param Q - Quality factor (default: 1.0)
* @returns New audio buffer with filter applied
*/
export async function applyLowPassFilter(
buffer: AudioBuffer,
frequency: number = 1000,
Q: number = 1.0
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'lowpass', frequency, Q });
}
/**
* Apply high-pass filter (cuts low frequencies)
* @param buffer - Source audio buffer
* @param frequency - Cutoff frequency in Hz (default: 100)
* @param Q - Quality factor (default: 1.0)
* @returns New audio buffer with filter applied
*/
export async function applyHighPassFilter(
buffer: AudioBuffer,
frequency: number = 100,
Q: number = 1.0
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'highpass', frequency, Q });
}
/**
* Apply band-pass filter (isolates a frequency range)
* @param buffer - Source audio buffer
* @param frequency - Center frequency in Hz (default: 1000)
* @param Q - Quality factor/bandwidth (default: 1.0)
* @returns New audio buffer with filter applied
*/
export async function applyBandPassFilter(
buffer: AudioBuffer,
frequency: number = 1000,
Q: number = 1.0
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'bandpass', frequency, Q });
}
/**
* Apply notch filter (removes a specific frequency)
* @param buffer - Source audio buffer
* @param frequency - Notch frequency in Hz (default: 1000)
* @param Q - Quality factor/bandwidth (default: 1.0)
* @returns New audio buffer with filter applied
*/
export async function applyNotchFilter(
buffer: AudioBuffer,
frequency: number = 1000,
Q: number = 1.0
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'notch', frequency, Q });
}
/**
* Apply low shelf filter (boost/cut low frequencies)
* @param buffer - Source audio buffer
* @param frequency - Shelf frequency in Hz (default: 200)
* @param gain - Gain in dB (default: 6)
* @returns New audio buffer with filter applied
*/
export async function applyLowShelfFilter(
buffer: AudioBuffer,
frequency: number = 200,
gain: number = 6
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'lowshelf', frequency, gain });
}
/**
* Apply high shelf filter (boost/cut high frequencies)
* @param buffer - Source audio buffer
* @param frequency - Shelf frequency in Hz (default: 3000)
* @param gain - Gain in dB (default: 6)
* @returns New audio buffer with filter applied
*/
export async function applyHighShelfFilter(
buffer: AudioBuffer,
frequency: number = 3000,
gain: number = 6
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'highshelf', frequency, gain });
}
/**
* Apply peaking EQ filter (boost/cut a specific frequency band)
* @param buffer - Source audio buffer
* @param frequency - Center frequency in Hz (default: 1000)
* @param Q - Quality factor/bandwidth (default: 1.0)
* @param gain - Gain in dB (default: 6)
* @returns New audio buffer with filter applied
*/
export async function applyPeakingFilter(
buffer: AudioBuffer,
frequency: number = 1000,
Q: number = 1.0,
gain: number = 6
): Promise<AudioBuffer> {
return applyFilter(buffer, { type: 'peaking', frequency, Q, gain });
}

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/**
* Gain/Volume adjustment effect
*/
import { getAudioContext } from '../context';
/**
* Apply gain to an audio buffer
* @param buffer - Source audio buffer
* @param gainValue - Gain multiplier (1.0 = no change, 0.5 = -6dB, 2.0 = +6dB)
* @returns New audio buffer with gain applied
*/
export function applyGain(buffer: AudioBuffer, gainValue: number): AudioBuffer {
const audioContext = getAudioContext();
const outputBuffer = audioContext.createBuffer(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
// Apply gain to each channel
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
outputData[i] = inputData[i] * gainValue;
// Clamp to prevent distortion
outputData[i] = Math.max(-1, Math.min(1, outputData[i]));
}
}
return outputBuffer;
}
/**
* Convert dB to gain multiplier
* @param db - Decibels
* @returns Gain multiplier
*/
export function dbToGain(db: number): number {
return Math.pow(10, db / 20);
}
/**
* Convert gain multiplier to dB
* @param gain - Gain multiplier
* @returns Decibels
*/
export function gainToDb(gain: number): number {
return 20 * Math.log10(gain);
}

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/**
* Normalization effects
*/
import { getAudioContext } from '../context';
/**
* Normalize audio to peak amplitude
* @param buffer - Source audio buffer
* @param targetPeak - Target peak amplitude (0.0 to 1.0, default 1.0)
* @returns New audio buffer with normalized audio
*/
export function normalizePeak(buffer: AudioBuffer, targetPeak: number = 1.0): AudioBuffer {
const audioContext = getAudioContext();
// Find the absolute peak across all channels
let maxPeak = 0;
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const channelData = buffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
const abs = Math.abs(channelData[i]);
if (abs > maxPeak) {
maxPeak = abs;
}
}
}
// Calculate gain factor
const gainFactor = maxPeak > 0 ? targetPeak / maxPeak : 1.0;
// Create output buffer and apply gain
const outputBuffer = audioContext.createBuffer(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
outputData[i] = inputData[i] * gainFactor;
}
}
return outputBuffer;
}
/**
* Normalize audio to RMS (loudness)
* @param buffer - Source audio buffer
* @param targetRMS - Target RMS level (0.0 to 1.0, default 0.5)
* @returns New audio buffer with normalized audio
*/
export function normalizeRMS(buffer: AudioBuffer, targetRMS: number = 0.5): AudioBuffer {
const audioContext = getAudioContext();
// Calculate RMS across all channels
let sumSquares = 0;
let totalSamples = 0;
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const channelData = buffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
sumSquares += channelData[i] * channelData[i];
totalSamples++;
}
}
const currentRMS = Math.sqrt(sumSquares / totalSamples);
const gainFactor = currentRMS > 0 ? targetRMS / currentRMS : 1.0;
// Create output buffer and apply gain
const outputBuffer = audioContext.createBuffer(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
outputData[i] = inputData[i] * gainFactor;
// Clamp to prevent distortion
outputData[i] = Math.max(-1, Math.min(1, outputData[i]));
}
}
return outputBuffer;
}
/**
* Get peak amplitude of audio buffer
* @param buffer - Audio buffer
* @returns Peak amplitude (0.0 to 1.0)
*/
export function getPeakAmplitude(buffer: AudioBuffer): number {
let maxPeak = 0;
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const channelData = buffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
const abs = Math.abs(channelData[i]);
if (abs > maxPeak) {
maxPeak = abs;
}
}
}
return maxPeak;
}
/**
* Get RMS amplitude of audio buffer
* @param buffer - Audio buffer
* @returns RMS amplitude
*/
export function getRMSAmplitude(buffer: AudioBuffer): number {
let sumSquares = 0;
let totalSamples = 0;
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const channelData = buffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
sumSquares += channelData[i] * channelData[i];
totalSamples++;
}
}
return Math.sqrt(sumSquares / totalSamples);
}

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@@ -0,0 +1,31 @@
/**
* Reverse audio effect
*/
import { getAudioContext } from '../context';
/**
* Reverse audio buffer
* @param buffer - Source audio buffer
* @returns New audio buffer with reversed audio
*/
export function reverseAudio(buffer: AudioBuffer): AudioBuffer {
const audioContext = getAudioContext();
const outputBuffer = audioContext.createBuffer(
buffer.numberOfChannels,
buffer.length,
buffer.sampleRate
);
// Reverse each channel
for (let channel = 0; channel < buffer.numberOfChannels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
for (let i = 0; i < buffer.length; i++) {
outputData[i] = inputData[buffer.length - 1 - i];
}
}
return outputBuffer;
}

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@@ -0,0 +1,128 @@
/**
* Utilities for applying effects to audio selections
*/
import type { Selection } from '@/types/selection';
import { getAudioContext } from '../context';
/**
* Extract a region from an audio buffer
*/
export function extractRegion(
buffer: AudioBuffer,
startTime: number,
endTime: number
): AudioBuffer {
const audioContext = getAudioContext();
const sampleRate = buffer.sampleRate;
const numberOfChannels = buffer.numberOfChannels;
const startSample = Math.floor(startTime * sampleRate);
const endSample = Math.floor(endTime * sampleRate);
const length = endSample - startSample;
const regionBuffer = audioContext.createBuffer(
numberOfChannels,
length,
sampleRate
);
for (let channel = 0; channel < numberOfChannels; channel++) {
const sourceData = buffer.getChannelData(channel);
const targetData = regionBuffer.getChannelData(channel);
for (let i = 0; i < length; i++) {
targetData[i] = sourceData[startSample + i];
}
}
return regionBuffer;
}
/**
* Replace a region in an audio buffer with processed audio
*/
export function replaceRegion(
originalBuffer: AudioBuffer,
processedRegion: AudioBuffer,
startTime: number
): AudioBuffer {
const audioContext = getAudioContext();
const sampleRate = originalBuffer.sampleRate;
const numberOfChannels = originalBuffer.numberOfChannels;
// Create new buffer with same length as original
const newBuffer = audioContext.createBuffer(
numberOfChannels,
originalBuffer.length,
sampleRate
);
const startSample = Math.floor(startTime * sampleRate);
for (let channel = 0; channel < numberOfChannels; channel++) {
const originalData = originalBuffer.getChannelData(channel);
const processedData = processedRegion.getChannelData(channel);
const newData = newBuffer.getChannelData(channel);
// Copy everything from original
for (let i = 0; i < originalBuffer.length; i++) {
newData[i] = originalData[i];
}
// Replace the selected region with processed data
for (let i = 0; i < processedRegion.length; i++) {
if (startSample + i < newBuffer.length) {
newData[startSample + i] = processedData[i];
}
}
}
return newBuffer;
}
/**
* Apply an effect function to a selection, or entire buffer if no selection
*/
export function applyEffectToSelection(
buffer: AudioBuffer,
selection: Selection | null,
effectFn: (buffer: AudioBuffer) => AudioBuffer
): AudioBuffer {
if (!selection || selection.start === selection.end) {
// No selection, apply to entire buffer
return effectFn(buffer);
}
// Extract the selected region
const region = extractRegion(buffer, selection.start, selection.end);
// Apply effect to the region
const processedRegion = effectFn(region);
// Replace the region in the original buffer
return replaceRegion(buffer, processedRegion, selection.start);
}
/**
* Apply an async effect function to a selection, or entire buffer if no selection
*/
export async function applyAsyncEffectToSelection(
buffer: AudioBuffer,
selection: Selection | null,
effectFn: (buffer: AudioBuffer) => Promise<AudioBuffer>
): Promise<AudioBuffer> {
if (!selection || selection.start === selection.end) {
// No selection, apply to entire buffer
return await effectFn(buffer);
}
// Extract the selected region
const region = extractRegion(buffer, selection.start, selection.end);
// Apply effect to the region
const processedRegion = await effectFn(region);
// Replace the region in the original buffer
return replaceRegion(buffer, processedRegion, selection.start);
}

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@@ -0,0 +1,340 @@
/**
* Time-based effects (Delay, Reverb, Chorus, Flanger, Phaser)
*/
import { getAudioContext } from '../context';
export interface DelayParameters {
time: number; // ms - delay time
feedback: number; // 0-1 - amount of delayed signal fed back
mix: number; // 0-1 - dry/wet mix (0 = dry, 1 = wet)
}
export interface ReverbParameters {
roomSize: number; // 0-1 - size of the reverb room
damping: number; // 0-1 - high frequency damping
mix: number; // 0-1 - dry/wet mix
}
export interface ChorusParameters {
rate: number; // Hz - LFO rate
depth: number; // 0-1 - modulation depth
delay: number; // ms - base delay time
mix: number; // 0-1 - dry/wet mix
}
export interface FlangerParameters {
rate: number; // Hz - LFO rate
depth: number; // 0-1 - modulation depth
feedback: number; // 0-1 - feedback amount
delay: number; // ms - base delay time
mix: number; // 0-1 - dry/wet mix
}
export interface PhaserParameters {
rate: number; // Hz - LFO rate
depth: number; // 0-1 - modulation depth
feedback: number; // 0-1 - feedback amount
stages: number; // 2-12 - number of allpass filters
mix: number; // 0-1 - dry/wet mix
}
/**
* Apply delay/echo effect to audio buffer
*/
export async function applyDelay(
buffer: AudioBuffer,
params: DelayParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Calculate delay in samples
const delaySamples = Math.floor((params.time / 1000) * sampleRate);
// Create output buffer (needs extra length for delay tail)
const outputLength = length + delaySamples * 5; // Allow for multiple echoes
const outputBuffer = audioContext.createBuffer(channels, outputLength, sampleRate);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
// Copy input and add delayed copies with feedback
for (let i = 0; i < outputLength; i++) {
let sample = 0;
// Add original signal
if (i < length) {
sample += inputData[i] * (1 - params.mix);
}
// Add delayed signal with feedback
let delayIndex = i;
let feedbackGain = params.mix;
for (let echo = 0; echo < 10; echo++) {
delayIndex -= delaySamples;
if (delayIndex >= 0 && delayIndex < length) {
sample += inputData[delayIndex] * feedbackGain;
}
feedbackGain *= params.feedback;
if (feedbackGain < 0.001) break; // Stop when feedback is negligible
}
outputData[i] = sample;
}
}
return outputBuffer;
}
/**
* Apply simple algorithmic reverb to audio buffer
*/
export async function applyReverb(
buffer: AudioBuffer,
params: ReverbParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Reverb uses multiple delay lines (Schroeder reverb algorithm)
const combDelays = [1557, 1617, 1491, 1422, 1277, 1356, 1188, 1116].map(
d => Math.floor(d * params.roomSize * (sampleRate / 44100))
);
const allpassDelays = [225, 556, 441, 341].map(
d => Math.floor(d * (sampleRate / 44100))
);
// Create output buffer with reverb tail
const outputLength = length + Math.floor(sampleRate * 3 * params.roomSize);
const outputBuffer = audioContext.createBuffer(channels, outputLength, sampleRate);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
// Comb filter buffers
const combBuffers = combDelays.map(delay => new Float32Array(delay));
const combIndices = combDelays.map(() => 0);
// Allpass filter buffers
const allpassBuffers = allpassDelays.map(delay => new Float32Array(delay));
const allpassIndices = allpassDelays.map(() => 0);
// Process samples
for (let i = 0; i < outputLength; i++) {
let input = i < length ? inputData[i] : 0;
let combSum = 0;
// Parallel comb filters
for (let c = 0; c < combDelays.length; c++) {
const delayedSample = combBuffers[c][combIndices[c]];
combSum += delayedSample;
// Feedback with damping
const feedback = delayedSample * (0.84 - params.damping * 0.2);
combBuffers[c][combIndices[c]] = input + feedback;
combIndices[c] = (combIndices[c] + 1) % combDelays[c];
}
// Average comb outputs
let sample = combSum / combDelays.length;
// Series allpass filters
for (let a = 0; a < allpassDelays.length; a++) {
const delayed = allpassBuffers[a][allpassIndices[a]];
const output = -sample + delayed;
allpassBuffers[a][allpassIndices[a]] = sample + delayed * 0.5;
sample = output;
allpassIndices[a] = (allpassIndices[a] + 1) % allpassDelays[a];
}
// Mix dry and wet
outputData[i] = input * (1 - params.mix) + sample * params.mix * 0.5;
}
}
return outputBuffer;
}
/**
* Apply chorus effect to audio buffer
*/
export async function applyChorus(
buffer: AudioBuffer,
params: ChorusParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Create output buffer
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Base delay in samples
const baseDelaySamples = (params.delay / 1000) * sampleRate;
const maxDelaySamples = baseDelaySamples + (params.depth * sampleRate * 0.005);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
// Create delay buffer
const delayBuffer = new Float32Array(Math.ceil(maxDelaySamples) + 1);
let delayIndex = 0;
for (let i = 0; i < length; i++) {
const input = inputData[i];
// Calculate LFO (Low Frequency Oscillator)
const lfoPhase = (i / sampleRate) * params.rate * 2 * Math.PI;
const lfo = Math.sin(lfoPhase);
// Modulated delay time
const modulatedDelay = baseDelaySamples + (lfo * params.depth * sampleRate * 0.005);
// Read from delay buffer with interpolation
const readIndex = (delayIndex - modulatedDelay + delayBuffer.length) % delayBuffer.length;
const readIndexInt = Math.floor(readIndex);
const readIndexFrac = readIndex - readIndexInt;
const sample1 = delayBuffer[readIndexInt];
const sample2 = delayBuffer[(readIndexInt + 1) % delayBuffer.length];
const delayedSample = sample1 + (sample2 - sample1) * readIndexFrac;
// Write to delay buffer
delayBuffer[delayIndex] = input;
delayIndex = (delayIndex + 1) % delayBuffer.length;
// Mix dry and wet
outputData[i] = input * (1 - params.mix) + delayedSample * params.mix;
}
}
return outputBuffer;
}
/**
* Apply flanger effect to audio buffer
*/
export async function applyFlanger(
buffer: AudioBuffer,
params: FlangerParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Create output buffer
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Base delay in samples (shorter than chorus)
const baseDelaySamples = (params.delay / 1000) * sampleRate;
const maxDelaySamples = baseDelaySamples + (params.depth * sampleRate * 0.002);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
// Create delay buffer
const delayBuffer = new Float32Array(Math.ceil(maxDelaySamples) + 1);
let delayIndex = 0;
for (let i = 0; i < length; i++) {
const input = inputData[i];
// Calculate LFO
const lfoPhase = (i / sampleRate) * params.rate * 2 * Math.PI;
const lfo = Math.sin(lfoPhase);
// Modulated delay time
const modulatedDelay = baseDelaySamples + (lfo * params.depth * sampleRate * 0.002);
// Read from delay buffer with interpolation
const readIndex = (delayIndex - modulatedDelay + delayBuffer.length) % delayBuffer.length;
const readIndexInt = Math.floor(readIndex);
const readIndexFrac = readIndex - readIndexInt;
const sample1 = delayBuffer[readIndexInt];
const sample2 = delayBuffer[(readIndexInt + 1) % delayBuffer.length];
const delayedSample = sample1 + (sample2 - sample1) * readIndexFrac;
// Write to delay buffer with feedback
delayBuffer[delayIndex] = input + delayedSample * params.feedback;
delayIndex = (delayIndex + 1) % delayBuffer.length;
// Mix dry and wet
outputData[i] = input * (1 - params.mix) + delayedSample * params.mix;
}
}
return outputBuffer;
}
/**
* Apply phaser effect to audio buffer
*/
export async function applyPhaser(
buffer: AudioBuffer,
params: PhaserParameters
): Promise<AudioBuffer> {
const audioContext = getAudioContext();
const channels = buffer.numberOfChannels;
const length = buffer.length;
const sampleRate = buffer.sampleRate;
// Create output buffer
const outputBuffer = audioContext.createBuffer(channels, length, sampleRate);
// Process each channel
for (let channel = 0; channel < channels; channel++) {
const inputData = buffer.getChannelData(channel);
const outputData = outputBuffer.getChannelData(channel);
// Allpass filter state for each stage
const stages = Math.floor(params.stages);
const allpassStates = new Array(stages).fill(0);
for (let i = 0; i < length; i++) {
let input = inputData[i];
let output = input;
// Calculate LFO
const lfoPhase = (i / sampleRate) * params.rate * 2 * Math.PI;
const lfo = Math.sin(lfoPhase);
// Modulated allpass frequency (200Hz to 2000Hz)
const baseFreq = 200 + (lfo + 1) * 0.5 * 1800 * params.depth;
const omega = (2 * Math.PI * baseFreq) / sampleRate;
const alpha = (1 - Math.tan(omega / 2)) / (1 + Math.tan(omega / 2));
// Apply cascaded allpass filters
for (let stage = 0; stage < stages; stage++) {
const filtered = alpha * output + allpassStates[stage];
allpassStates[stage] = output - alpha * filtered;
output = filtered;
}
// Add feedback
output = output + output * params.feedback;
// Mix dry and wet
outputData[i] = input * (1 - params.mix) + output * params.mix;
}
}
return outputBuffer;
}

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@@ -75,8 +75,10 @@ export class AudioPlayer {
pause(): void {
if (!this.isPlaying) return;
this.pauseTime = this.getCurrentTime();
// Save current time BEFORE calling stop (which resets it)
const savedTime = this.getCurrentTime();
this.stop();
this.pauseTime = savedTime;
this.isPaused = true;
}