/**
 * Utility functions for Web Worker communication and audio buffer handling
 */
import type { SerializableAudioBuffer } from './types';
/**
 * Convert an AudioBuffer to a serializable format that can be transferred
 * between threads efficiently using Transferable objects.
 *
 * @param audioBuffer - The AudioBuffer to serialize
 * @returns Serializable audio buffer with transferable Float32Arrays
 *
 * @example
 * ```typescript
 * const serializable = serializeAudioBuffer(audioBuffer);
 * worker.postMessage(
 *   { audioData: serializable },
 *   serializable.channelData // Transfer ownership
 * );
 * ```
 */
export declare function serializeAudioBuffer(audioBuffer: AudioBuffer): SerializableAudioBuffer;
/**
 * Convert a serializable audio buffer back to an AudioBuffer.
 * This function works in both main thread and worker contexts.
 *
 * @param serializable - The serializable audio buffer
 * @param audioContext - Optional AudioContext (required in main thread)
 * @returns A new AudioBuffer with the deserialized data
 *
 * @example
 * ```typescript
 * const audioBuffer = deserializeAudioBuffer(serializable, audioContext);
 * ```
 */
export declare function deserializeAudioBuffer(serializable: SerializableAudioBuffer, audioContext?: BaseAudioContext): AudioBuffer;
/**
 * Extract transferable objects from a serializable audio buffer.
 * Use this with postMessage to transfer ownership and avoid copying.
 *
 * @param serializable - The serializable audio buffer
 * @returns Array of transferable ArrayBuffers
 *
 * @example
 * ```typescript
 * const serializable = serializeAudioBuffer(audioBuffer);
 * const transferables = getTransferables(serializable);
 * worker.postMessage({ audioData: serializable }, transferables);
 * ```
 */
export declare function getTransferables(serializable: SerializableAudioBuffer): ArrayBuffer[];
/**
 * Generate a unique ID for worker requests
 *
 * @returns A unique identifier string
 */
export declare function generateId(): string;
/**
 * Create a promise that resolves after a specified timeout
 *
 * @param ms - Timeout in milliseconds
 * @returns Promise that resolves after the timeout
 */
export declare function delay(ms: number): Promise<void>;
/**
 * Create a promise that rejects after a specified timeout
 *
 * @param ms - Timeout in milliseconds
 * @param message - Error message
 * @returns Promise that rejects after timeout
 */
export declare function timeout<T>(ms: number, message?: string): Promise<T>;
/**
 * Race a promise against a timeout
 *
 * @param promise - The promise to race
 * @param ms - Timeout in milliseconds
 * @param message - Optional error message for timeout
 * @returns Promise that resolves/rejects with the first result
 */
export declare function withTimeout<T>(promise: Promise<T>, ms: number, message?: string): Promise<T>;
/**
 * Downsample audio data for waveform visualization
 *
 * @param audioBuffer - The audio buffer to downsample
 * @param targetSamples - Number of samples in the output (default: 1000)
 * @param channel - Which channel to use (default: 0, -1 for average)
 * @param useRMS - Use RMS values instead of peaks (default: false)
 * @returns Downsampled waveform data
 *
 * @example
 * ```typescript
 * const waveform = downsampleAudioBuffer(audioBuffer, 1000, 0, false);
 * ```
 */
export declare function downsampleAudioBuffer(audioBuffer: AudioBuffer, targetSamples?: number, channel?: number, useRMS?: boolean): Float32Array;
/**
 * Validate that an audio buffer has valid parameters
 *
 * @param audioBuffer - The audio buffer to validate
 * @throws Error if the audio buffer is invalid
 */
export declare function validateAudioBuffer(audioBuffer: AudioBuffer): void;
/**
 * Validate pitch shift parameters
 *
 * @param pitch - Pitch in semitones
 * @throws Error if pitch is out of range
 */
export declare function validatePitch(pitch: number): void;
/**
 * Validate speed parameters
 *
 * @param speed - Speed multiplier
 * @throws Error if speed is out of range
 */
export declare function validateSpeed(speed: number): void;
/**
 * Validate mix parameter
 *
 * @param mix - Wet/dry mix (0-1)
 * @throws Error if mix is out of range
 */
export declare function validateMix(mix: number): void;
/**
 * Calculate the expected output length for time-stretched audio
 *
 * @param inputLength - Length of input audio in samples
 * @param speed - Speed multiplier
 * @returns Expected output length in samples
 */
export declare function calculateOutputLength(inputLength: number, speed: number): number;
/**
 * Format bytes as human-readable string
 *
 * @param bytes - Number of bytes
 * @returns Formatted string (e.g., "1.5 MB")
 */
export declare function formatBytes(bytes: number): string;
/**
 * Format duration in seconds as human-readable string
 *
 * @param seconds - Duration in seconds
 * @returns Formatted string (e.g., "2:30" or "1:05:30")
 */
export declare function formatDuration(seconds: number): string;
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