music-metadata

Key features:

• Comprehensive Format Support: Supports popular audio formats like MP3, MP4, FLAC, Ogg, WAV, AIFF, and more.
• Extensive Metadata Extraction: Extracts detailed metadata, including ID3v1, ID3v2, APE, Vorbis, and iTunes/MP4 tags.
• Streaming Support: Efficiently handles large audio files by reading metadata from streams, making it suitable for server-side and browser-based applications.
• Promise-Based API: Provides a modern, promise-based API for easy integration into asynchronous workflows.
• Cross-Platform: Works in both Node.js and browser environments with the help of bundlers like Webpack or Rollup.

The music-metadata module is ideal for developers working on media applications, music players, or any project that requires access to detailed audio file metadata.

Compatibility

Module: version 8 migrated from CommonJS to pure ECMAScript Module (ESM). The distributed JavaScript codebase is compliant with the ECMAScript 2020 (11th Edition) standard.

Note

See also CommonJS Backward Compatibility

This module requires a Node.js ≥ 16 engine. It can also be used in a browser environment when bundled with a module bundler.

Sponsor

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Features

Support for audio file types

Audio format	Description	Wiki
AIFF / AIFF-C	Audio Interchange File Format	🔗
AAC	ADTS / Advanced Audio Coding	🔗
APE	Monkey's Audio	🔗
ASF	Advanced Systems Format	🔗
BWF	Broadcast Wave Format	🔗
DSDIFF	Philips DSDIFF	🔗
DSF	Sony's DSD Stream File	🔗
FLAC	Free Lossless Audio Codec	🔗
MP2	MPEG-1 Audio Layer II	🔗
Matroska	Matroska (EBML), mka, mkv	🔗
MP3	MPEG-1 / MPEG-2 Audio Layer III	🔗
MPC	Musepack SV7	🔗
MPEG 4	mp4, m4a, m4v	🔗
Ogg	Open container format	🔗
Opus		🔗
Speex		🔗
Theora		🔗
Vorbis	Vorbis audio compression	🔗
WAV	RIFF WAVE	🔗
WebM	webm	🔗
WV	WavPack	🔗
WMA	Windows Media Audio	🔗

Supported tag headers

Following tag header formats are supported:

• APE
• ASF
• EXIF 2.3
• ID3: ID3v1, ID3v1.1, ID3v2.2, ID3v2.3 & ID3v2.4
• iTunes
• RIFF/INFO
• Vorbis comment
• AIFF

It allows many tags to be accessed in audio format, and tag format independent way.

Support for MusicBrainz tags as written by Picard. ReplayGain tags are supported.

Audio format & encoding details

Support for encoding / format details:

• Bit rate
• Audio bit depth
• Duration
• Encoding profile (e.g. CBR, V0, V2)

Online demo's

• Audio Tag Analyzer
• Webamp
• Expected to be released soon: Overtone by Johannes Schickling

Usage

Installation

Install using npm:

npm install music-metadata

or using yarn:

yarn add music-metadata

API Documentation

Overview

Node.js specific functions to read an audio file or stream:

1. File Parsing: Parse audio files directly from the filesystem using the parseFile function
2. Stream Parsing: Parse audio metadata from a Node.js Readable stream using the parseStream function.

Cross-platform functions available to read an audio file or stream:

There are multiple ways to parse (read) audio tracks:

1. Web Stream Parsing: Parse audio data from a web-compatible ReadableStream using the parseWebStream function.
2. Blob Parsing: Parse audio metadata from a (Web API) Blob or File using the parseBlob function.
3. Buffer Parsing: Parse audio metadata from a Uint8Array or Buffer using the parseBuffer function.
4. Tokenizer Parsing: Use a custom or third-party strtok3 ITokenizer to parse using the parseFromTokenizer function.

Note

Direct file access in Node.js is generally faster because it can 'jump' to various parts of the file without reading intermediate data.

Node.js specific function

These functions are tailored for Node.js environments and leverage Node.js-specific APIs, making them incompatible with browser-based JavaScript engines.

parseFile function

The parseFile function is intended for extracting metadata from audio files on the local filesystem in a Node.js environment. It reads the specified file, parses its audio metadata, and returns a promise that resolves with this information.

Syntax

parseFile(filePath: string, options?: IOptions): Promise<IAudioMetadata>

Parameters

• filePath: string

  The path to the media file from which metadata should be extracted. This should be a valid path to an audio file on the local filesystem.

• options: IOptions (optional)

  An optional configuration object that allows customization of the parsing process. These options can include whether to calculate the file's duration, skip embedded cover art, or other parsing behaviors.

Returns

• Promise<IAudioMetadata>:

  A promise that resolves to an IAudioMetadata object containing metadata about the audio file. The metadata includes details such as the file format, codec, duration, bit rate, and any embedded tags like album, artist, or track information.

Usage Notes

• This function is Node.js-only and relies on Node.js-specific APIs to access the filesystem.

• For browser environments, consider using the parseBlob to parse File object objects.

Example:

The following example demonstrates how to use the parseFile function to read metadata from an audio file:

import { parseFile } from 'music-metadata';
import { inspect } from 'util';

(async () => {
  try {
    const filePath = '../music-metadata/test/samples/MusicBrainz - Beth Hart - Sinner\'s Prayer [id3v2.3].V2.mp3';
    const metadata = await parseFile(filePath);

    // Output the parsed metadata to the console in a readable format
    console.log(inspect(metadata, { showHidden: false, depth: null }));
  } catch (error) {
    console.error('Error parsing metadata:', error.message);
  }
})();

parseStream function

The parseStream function is used to parse metadata from an audio track provided as a Node.js Readable stream. This is particularly useful for processing audio data that is being streamed or piped from another source, such as a web server or file system.

Syntax:

parseStream(stream: Readable, fileInfo?: IFileInfo | string, options?: IOptions): Promise<IAudioMetadata>

Parameters:

• stream: Readable:

  The Node.js Readable stream from which the audio data is read. This stream should provide the raw audio data to be analyzed.

• fileInfo: IFileInfo (optional)

  An object containing file-related information or a string representing the MIME-type of the audio stream. The fileInfo parameter can help the parser to correctly identify the audio format and may include:

  • mimeType: A string representing the MIME-type (e.g., audio/mpeg).

    If provided, it is assumed the streamed file content is to be the MIME-type. If not provided, the parser will attempt to determine the format based on the content of the stream.

  • size: The total size of the audio stream in bytes (useful for streams with a known length).

  • path: A string representing the file path or filename, which can also assist in determining the format.

• options: IOptions (optional)

  An optional object containing additional parsing options. These options allow you to customize the parsing process, such as whether to calculate the duration or skip cover art extraction.

Returns

• Promise<IAudioMetadata>:

  A promise that resolves to an IAudioMetadata object containing detailed metadata about the audio stream. This metadata includes information about the format, codec, duration, bitrate, and any embedded tags such as artist, album, or track information.

Usage Notes

• This function is only available in Node.js environments, as it relies on the Node.js stream API.

Example:

The following example demonstrates how to use the parseStream function to read metadata from an audio stream:

import { parseStream } from 'music-metadata';
import { createReadStream } from 'fs';

(async () => {
  try {
    // Create a readable stream from a file
    const audioStream = createReadStream('path/to/audio/file.mp3');

    // Parse the metadata from the stream
    const metadata = await parseStream(audioStream, { mimeType: 'audio/mpeg'});

    // Log the parsed metadata
    console.log(metadata);
  } catch (error) {
    console.error('Error parsing metadata:', error.message);
  }
})();

Cross-platform functions

These functions are designed to be cross-platform, meaning it can be used in both Node.js and web browsers.

parseWebStream function

The parseWebStream function is used to extract metadata from an audio track provided as a web-compatible ReadableStream. This function is ideal for applications running in web environments, such as browsers, where audio data is streamed over the network or read from other web-based sources.

Syntax

parseWebStream(webStream: ReadableStream<Uint8Array>, fileInfo?: IFileInfo | string, options?: IOptions): Promise<IAudioMetadata>

Parameters

• webStream: ReadableStream<Uint8Array>

  A ReadableStream that provides the audio data to be parsed. This stream should emit Uint8Array chunks, representing the raw audio data.

• fileInfo: IFileInfo (optional)

  An object containing file-related information or a string representing the MIME-type of the audio stream. The fileInfo parameter can help the parser to correctly identify the audio format and may include:

  • mimeType: A string representing the MIME-type (e.g., audio/mpeg).

    If provided, it is assumed the streamed file content is to be the MIME-type. If not provided, the parser will attempt to determine the format based on the content of the stream.

  • size: The total size of the audio stream in bytes (useful for streams with a known length).

  • path: A string representing the file path or filename, which can also assist in determining the format.

• options: IOptions (optional)

  An optional object containing additional parsing options. These options allow you to customize the parsing process, such as whether to calculate the duration or skip cover art extraction.

Returns

• Promise<IAudioMetadata>:

  A promise that resolves to an IAudioMetadata object containing detailed metadata about the audio stream. This metadata includes information about the format, codec, duration, bitrate, and any embedded tags such as artist, album, or track information.

Example

Here’s an example of how to use the parseWebStream function to extract metadata from an audio stream in a web application:

import { parseWebStream } from 'music-metadata';

(async () => {
try {
// Assuming you have a ReadableStream of an audio file
const response = await fetch('https://example.com/path/to/audio/file.mp3');
const webStream = response.body;

    // Parse the metadata from the web stream
    const metadata = await parseWebStream(webStream, 'audio/mpeg');

    // Log the parsed metadata
    console.log(metadata);
} catch (error) {
console.error('Error parsing metadata:', error.message);
}
})();

The example uses the fetch API to retrieve an audio file from a URL. The response.body provides a ReadableStream that is then passed to parseWebStream.

parseBlob function

Parses metadata from an audio file represented as a Blob. This function is suitable for use in environments that support the ReadableStreamBYOBReader, which is available in Node.js 20 and above.

Syntax

parseBlob(blob: Blob, options?: IOptions = {}): Promise<IAudioMetadata>

Parameters

• blob: Blob

  The Blob object containing the audio data to be parsed. This can be a file or any binary data. If the Blob is an instance of File, its name will be used as the file path in the metadata.

• options: IOptions (optional)

  An optional configuration object that specifies parsing options.

Returns

• Promise<IAudioMetadata>:

  A promise that resolves to the metadata of the audio file.

Example

import { parseBlob } from 'music-metadata';

(async () => {
  const fileInput = document.querySelector('input[type="file"]');
  const file = fileInput.files[0];
  
  try {
    const metadata = await parseBlob(file);
    console.log(metadata);
  } catch (error) {
    console.error('Error parsing metadata:', error.message);
  }
})();

parseBuffer function

Parses metadata from an audio file where the audio data is held in a Uint8Array or Buffer. This function is particularly useful when you already have audio data in memory.

Syntax

parseBuffer(buffer: Uint8Array, fileInfo?: IFileInfo | string, opts?: IOptions = {}): Promise<IAudioMetadata>

Parameters

• uint8Array: Uint8Array

  A Uint8Array containing the audio data to be parsed.

• fileInfo: IFileInfo | string (optional)

  An object containing file information such as mimeType and size. Alternatively, you can pass a MIME-type string directly. This helps the parser understand the format of the audio data.

• options: IOptions (optional)

  An optional configuration object that specifies parsing options.

Returns

• Promise<IAudioMetadata>:

  A promise that resolves to the metadata of the audio file.

Example

import { parseBuffer } from 'music-metadata';
import fs from 'fs';

(async () => {
  const buffer = fs.readFileSync('path/to/audio/file.mp3');

  try {
    const metadata = await parseBuffer(buffer, { mimeType: 'audio/mpeg' });
    console.log(metadata);
  } catch (error) {
    console.error('Error parsing metadata:', error.message);
  }
})();

parseFromTokenizer function

Parses metadata from an audio source that implements the strtok3 ITokenizer interface. This is a low-level function that provides flexibility for advanced use cases, such as parsing metadata from streaming audio or custom data sources.

This also enables special read modules like:

• streaming-http-token-reader for chunked HTTP(S) reading, using HTTP range requests.

Syntax

parseFromTokenizer(tokenizer: ITokenizer, options?: IOptions): Promise<IAudioMetadata>

Parameters

• tokenizer: ITokenizer

  An instance of an ITokenizer that provides access to the audio data. The tokenizer abstracts the reading process, enabling support for various types of sources, including streams, buffers, or custom data readers.

• options: IOptions (optional)

  An optional configuration object that specifies parsing options.

Returns

• Promise<IAudioMetadata>:

  A promise that resolves to the metadata of the audio source, including information like the title, artist, album, and more.

Example

import { fromNodeProviderChain } from '@aws-sdk/credential-providers';
import { S3Client } from '@aws-sdk/client-s3';
import { makeTokenizer } from '@tokenizer/s3';
import { parseFromTokenizer as mmParseFromTokenizer } from 'music-metadata';

// Configure the S3 client
const s3 = new S3Client({
  region: 'eu-west-2',
  credentials: fromNodeProviderChain(),
});

// Helper function to create a tokenizer for S3 objects
async function makeS3TestDataTokenizer(key, options) {
  return await makeTokenizer(s3, {
    Bucket: 'music-metadata',
    Key: key,
  }, options);
}

// Function to read and log metadata from an S3 object
async function readMetadata() {
  try {
    // Create a tokenizer for the specified S3 object
    const tokenizer = await makeS3TestDataTokenizer('path/to/audio/file.mp3', { disableChunked: false });

    // Parse the metadata from the tokenizer
    const metadata = await mmParseFromTokenizer(tokenizer);

    // Log the retrieved metadata
    console.log(metadata);
  } catch (error) {
    console.error('Error parsing metadata:', error.message);
  }
}

// Execute the metadata reading function
readMetadata();

Additional Resources

• strtok3 - Learn more about the ITokenizer interface and how to implement it for various use cases.
• AWS SDK for JavaScript - Documentation on using the AWS SDK to interact with S3 and other AWS services.
• @tokenizer/s3 - Example of ITokenizer implementation.

Handling Parse Errors

music-metadata provides a robust and extensible error handling system with custom error classes that inherit from the standard JavaScript Error. All possible parsing errors are part of a union type UnionOfParseErrors, ensuring that every error scenario is accounted for in your code.

Union of Parse Errors

All parsing errors extend from the base class ParseError and are included in the UnionOfParseErrors type:

export type UnionOfParseErrors =
  | CouldNotDetermineFileTypeError
  | UnsupportedFileTypeError
  | UnexpectedFileContentError
  | FieldDecodingError
  | InternalParserError;

Error Types

• CouldNotDetermineFileTypeError: Raised when the file type cannot be determined.
• UnsupportedFileTypeError: Raised when an unsupported file type is encountered.
• UnexpectedFileContentError: Raised when the file content does not match the expected format.
• FieldDecodingError: Raised when a specific field in the file cannot be decoded.
• InternalParserError: Raised for internal parser errors.

Other functions

orderTags function

Utility to Converts the native tags to a dictionary index on the tag identifier

orderTags(nativeTags: ITag[]): [tagId: string]: any[]

import { parseFile, orderTags } from 'music-metadata';
import { inspect } from 'util';

(async () => {
  try {
    const metadata = await parseFile('../test/samples/MusicBrainz - Beth Hart - Sinner\'s Prayer [id3v2.3].V2.mp3');
    const orderedTags = orderTags(metadata.native['ID3v2.3']);
    console.log(inspect(orderedTags, { showHidden: false, depth: null }));
  } catch (error) {
    console.error(error.message);
  }
})();

ratingToStars function

Can be used to convert the normalized rating value to the 0..5 stars, where 0 an undefined rating, 1 the star the lowest rating and 5 the highest rating.

ratingToStars(rating: number): number

selectCover function

Select cover image based on image type field, otherwise the first picture in file.

export function selectCover(pictures?: IPicture[]): IPicture | null

import { parseFile, selectCover } from 'music-metadata';

(async () => {
  const {common} = await parseFile(filePath);
  const cover = selectCover(common.picture); // pick the cover image
}
)();

IOptions Interface

• duration: boolean (default: false)

  If set to true, the parser will analyze the entire media file, if necessary, to determine its duration. This option ensures accurate duration calculation but may increase processing time for large files.

• observer: (update: MetadataEvent) => void;:

  A callback function that is invoked whenever there is an update to the common (generic) tag or format properties during parsing. This allows for real-time updates on metadata changes.

• skipCovers: boolean (default: false)

  If set to true, the parser will skip the extraction of embedded cover art (images) from the media file. This can be useful to avoid processing unnecessary data if cover images are not required.

• mkvUseIndex: boolean (default: false)

  If set to true, the parser will use the SeekHead element index to skip segment/cluster elements in Matroska-based files. This is an experimental feature and can significantly impact performance. It may also result in some metadata being skipped if it is not indexed. If the SeekHead element is absent in the Matroska file, this flag has no effect.

Note

• The duration option is typically included in most cases, but setting it to true ensures that the entire file is parsed if necessary to get an accurate duration.
• Using mkvUseIndex can improve performance in Matroska files, but be aware of potential side effects, such as missing metadata due to skipped elements.

IAudioMetadata interface

If the returned promise resolves, the metadata (TypeScript IAudioMetadata interface) contains:

• metadata.format Audio format information
• metadata.common Is a generic (abstract) way of reading metadata information.
• metadata.trackInfo Is a generic (abstract) way of reading metadata information.
• metadata.native List of native (original) tags found in the parsed audio file.

metadata.format

The questionmark ? indicates the property is optional.

Audio format information. Defined in the TypeScript IFormat interface:

• format.container?: string Audio encoding format. e.g.: 'flac'
• format.codec? Name of the codec (algorithm used for the audio compression)
• format.codecProfile?: string Codec profile / settings
• format.tagTypes?: TagType[] List of tagging formats found in parsed audio file
• format.duration?: number Duration in seconds
• format.bitrate?: number Number bits per second of encoded audio file
• format.sampleRate?: number Sampling rate in Samples per second (S/s)
• format.bitsPerSample?: number Audio bit depth
• format.lossless?: boolean True if lossless, false for lossy encoding
• format.numberOfChannels?: number Number of audio channels
• format.creationTime?: Date Track creation time
• format.modificationTime?: Date Track modification / tag update time
• format.trackGain?: number Track gain in dB
• format.albumGain?: number Album gain in dB

metadata.trackInfo

To support advanced containers like Matroska or MPEG-4, which may contain multiple audio and video tracks, the experimental- metadata.trackInfo has been added,

metadata.trackInfo is either undefined or has an array of trackInfo

trackInfo

Audio format information. Defined in the TypeScript IFormat interface:

• trackInfo.type?: TrackType Track type
• trackInfo.codecName?: string Codec name
• trackInfo.codecSettings?: string Codec settings
• trackInfo.flagEnabled?: boolean Set if the track is usable, default: true
• trackInfo.flagDefault?: boolean Set if that track (audio, video or subs) SHOULD be active if no language found matches the user preference.
• trackInfo.flagLacing?: boolean Set if the track may contain blocks using lacing
• trackInfo.name?: string A human-readable track name.
• trackInfo.language?: string Specifies the language of the track
• trackInfo.audio?: IAudioTrack, see trackInfo.audioTrack
• trackInfo.video?: IVideoTrack, see trackInfo.videoTrack

trackInfo.audioTrack

• audioTrack.samplingFrequency?: number
• audioTrack.outputSamplingFrequency?: number
• audioTrack.channels?: number
• audioTrack.channelPositions?: Buffer
• audioTrack.bitDepth?: number

trackInfo.videoTrack

• videoTrack.flagInterlaced?: boolean
• videoTrack.stereoMode?: number
• videoTrack.pixelWidth?: number
• videoTrack.pixelHeight?: number
• videoTrack.displayWidth?: number
• videoTrack.displayHeight?: number
• videoTrack.displayUnit?: number
• videoTrack.aspectRatioType?: number
• videoTrack.colourSpace?: Buffer
• videoTrack.gammaValue?: number

metadata.common

Common tag documentation is automatically generated.

Examples

In order to read the duration of a stream (with the exception of file streams), in some cases you should pass the size of the file in bytes.

import { parseStream } from 'music-metadata';
import { inspect } from 'util';

(async () => {
    const metadata = await parseStream(someReadStream, {mimeType: 'audio/mpeg', size: 26838}, {duration: true});
    console.log(inspect(metadata, {showHidden: false, depth: null}));
    someReadStream.close();
  }
)();

Access cover art

Via metadata.common.picture you can access an array of cover art if present. Each picture has this interface:

/**
 * Attached picture, typically used for cover art
 */
export interface IPicture {
  /**
   * Image mime type
   */
  format: string;
  /**
   * Image data
   */
  data: Buffer;
  /**
   * Optional description
   */
  description?: string;
  /**
   * Picture type
   */
  type?: string;
}

To assign img HTML-object you can do something like:

import {uint8ArrayToBase64} from 'uint8array-extras';

img.src = `data:${picture.format};base64,${uint8ArrayToBase64(picture.data)}`;

Dependencies

Dependency diagram:

graph TD;
    MMN("music-metadata (Node.js entry point)")-->MMP
    MMN-->FTN
    MMP("music-metadata (primary entry point)")-->S(strtok3)
    MMP-->TY(token-types)
    MMP-->FTP
    MMP-->UAE
    FTN("file-type (Node.js entry point)")-->FTP
    FTP("file-type (primary entry point)")-->S
    S(strtok3)-->P(peek-readable)
    S(strtok3)-->TO("@tokenizer/token")
    TY(token-types)-->TO
    TY-->IE("ieee754")
    FTP-->TY
    NS("node:stream")
    FTN-->NS
    FTP-->UAE(uint8array-extras)
    style NS fill:#F88,stroke:#A44
    style IE fill:#CCC,stroke:#888
    style FTN fill:#FAA,stroke:#A44
    style MMN fill:#FAA,stroke:#A44

Loading

Dependency list:

• tokenizer-token
• strtok3
• token-types
• file-type
• @tokenizer-token
• peek-readable

CommonJS Backward compatibility

For legacy CommonJS projects needing to load the music-metadata ESM module, you can use the loadMusicMetadata function:

const { loadMusicMetadata } = require('music-metadata');

(async () => {
  // Dynamically loads the ESM module in a CommonJS project
  const mm = await loadMusicMetadata();

  const metadata = await mm.parseFile('/path/to/your/file');
})();

Note

The loadMusicMetadata function is experimental and is not currently covered by any TypeScript typings.

Frequently Asked Questions

1. How can I traverse (a long) list of files?

   What is important that file parsing should be done in a sequential manner. In a plain loop, due to the asynchronous character (like most JavaScript functions), it would cause all the files to run in parallel which is will cause your application to hang in no time. There are multiple ways of achieving this:

   1. Using recursion

      import { parseFile } from 'music-metadata';
      
      function parseFiles(audioFiles) {
      
        const audioFile = audioFiles.shift();
      
        if (audioFile) {
          return parseFile(audioFile).then(metadata => {
            // Do great things with the metadata
            return parseFiles(audioFiles); // process rest of the files AFTER we are finished
          })
        }
      }

   2. Use async/await

      Use async/await

      import { parseFile } from 'music-metadata';
      
      // it is required to declare the function 'async' to allow the use of await
      async function parseFiles(audioFiles) {
      
          for (const audioFile of audioFiles) {
      
              // await will ensure the metadata parsing is completed before we move on to the next file
              const metadata = await parseFile(audioFile);
              // Do great things with the metadata
          }
      }

Licence

The MIT License (MIT)

Copyright © 2024 Borewit

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.