@napi-audio/decoder-stream

For information about supported codecs, containers, and runtime platforms see @napi-audio/decoder.

A streaming interface for @napi-audio/decoder.

Getting Started

# With npm
npm install @napi-audio/decoder-stream

# With pnpm
pnpm install @napi-audio/decoder-stream

# With yarn
yarn add @napi-audio/decoder-stream

Usage

import { createReadStream, createWriteStream } from "node:fs";
import { DecoderStream } from "@napi-audio/decoder-stream";

// create a read stream from an audio file
createReadStream("./audio-file.mp3")
  // pipe the stream into an instance of DecoderStream
  .pipe(
    new DecoderStream({
      // don't enable gapless decoding (optional, disabled by default)
      enableGapless: false,
      // a hint about the audio format (optional, recommended)
      mimeType: "audio/mpeg3",
      // a hint about the audio container (optional, recommended)
      fileExtension: "mp3",
      // Callback to be invoked when the decoder detects the metadata of the underlying audio.
      // this is optional, but highly recommended if you're doing additional audio processing.
      onMetadataDetected(channelCount, sampleRate) {
        console.log(
          `Audio stream contains ${channelCount} channels @ ${sampleRate}hz`
        );
      },
    })
  )
  // pipe the decoded audio to an output file stream
  // note that the format is always interleaved PCM audio (Signed 16-bit PCM, Little-Endian)
  .pipe(createWriteStream("./audio-file.pcm"));

// The generated file can be inspected with Audacity, using File => Import => Raw Data

Debugging

The native library is written in Rust, and can output tracing information if configured to do so. The setNativeTracing export can be used for this - pass true to enable logging, or false to disable. You'll also need to ensure the RUST_LOG environment variable is set according to the EnvFilter docs; for example RUST_LOG=trace. Note that tracing disabled by default.

Licensing

Source Code

This source is licensed under MPL-2.0.

Codecs

I am a software developer, not a lawyer. If you're using this in production you should consult a lawyer.

If you're using this library to parse certain media formats and codecs, you may need to pay royalties. For more information, see Symphonia Docs and/or this Google search.