Async Audio Stream

Async Audio Stream defines abstract interfaces for streaming audio data in an asynchronous, format-agnostic way. This is ideal for real-time audio processing pipelines, including transcoding, streaming, and speech recognition workflows.

Install

npm install @silyze/async-audio-stream

Usage

Import and use it in your project:

import { AudioFormat, AudioStream } from "@silyze/async-audio-stream";

// Example: Implement your custom audio format
class MyFormat extends AudioFormat {
  get name() {
    return "my-format";
  }

  get pcmSampleRate() {
    return 48000;
  }

  decode(input: AsyncReadStream<Buffer>): AsyncReadStream<Buffer> {
    // return a PCM stream
    throw new Error("Not implemented");
  }

  encode(input: AsyncReadStream<Buffer>): AsyncReadStream<Buffer> {
    // return an encoded stream
    throw new Error("Not implemented");
  }
}

Interfaces

AudioFormat

Represents an audio encoding format. You must implement:

abstract class AudioFormat {
  abstract decode(input: AsyncReadStream<Buffer>): AsyncReadStream<Buffer>;
  abstract encode(input: AsyncReadStream<Buffer>): AsyncReadStream<Buffer>;

  abstract get name(): string;
  abstract get pcmSampleRate(): number;
}

• decode() — Converts from this format to PCM.
• encode() — Converts from PCM to this format.
• name — Human-readable identifier.
• pcmSampleRate — The PCM sample rate used in decode/encode.

AudioOutputStream

interface AudioOutputStream extends AsyncReadStream<Buffer> {
  get format(): AudioFormat;
}

Represents a readable audio stream with associated format metadata.

AudioInputStream

interface AudioInputStream extends AsyncWriteStream<Buffer> {
  get format(): AudioFormat;
}

Represents a writable audio stream with associated format metadata.

AudioStream

interface AudioStream extends AudioInputStream, AudioOutputStream {
  get ready(): Promise<void>;
}

Bidirectional stream that supports both input and output. Useful for transcoders or duplex pipelines.

• ready — A promise that resolves when the stream is ready to use.

Transcript

interface Transcript {
  source: string;
  content: string;
}

Represents a unit of transcription output.

Implementation Guide

To implement a custom format or stream:

1. Implement AudioFormat for your codec.
2. Use AsyncReadStream and AsyncWriteStream (from @mojsoski/async-stream) for streaming behavior.
3. Wrap AudioStream if you need to create a full duplex audio processor or transcoder.