music-metadata

What is music-metadata?

The music-metadata npm package is a powerful tool for parsing and extracting metadata from audio files. It supports a wide range of audio formats and provides detailed information about the audio file, including tags, format, and technical properties.

What are music-metadata's main functionalities?

Extract Basic Metadata

This feature allows you to extract basic metadata from an audio file, such as title, artist, album, and genre. The code sample demonstrates how to use the `parseFile` method to read and log metadata from an MP3 file.

const mm = require('music-metadata');
const fs = require('fs');

async function getMetadata(filePath) {
  try {
    const metadata = await mm.parseFile(filePath);
    console.log(metadata);
  } catch (error) {
    console.error(error.message);
  }
}

getMetadata('path/to/audio/file.mp3');

Extract Format Information

This feature allows you to extract format information from an audio file, such as the container type, codec, sample rate, and bit rate. The code sample demonstrates how to use the `parseFile` method to read and log format information from an MP3 file.

const mm = require('music-metadata');
const fs = require('fs');

async function getFormatInfo(filePath) {
  try {
    const metadata = await mm.parseFile(filePath);
    console.log(metadata.format);
  } catch (error) {
    console.error(error.message);
  }
}

getFormatInfo('path/to/audio/file.mp3');

Extract Technical Properties

This feature allows you to extract technical properties from an audio file, such as duration, number of channels, and bit depth. The code sample demonstrates how to use the `parseFile` method to read and log technical properties from an MP3 file.

const mm = require('music-metadata');
const fs = require('fs');

async function getTechnicalProperties(filePath) {
  try {
    const metadata = await mm.parseFile(filePath);
    console.log(metadata.common);
  } catch (error) {
    console.error(error.message);
  }
}

getTechnicalProperties('path/to/audio/file.mp3');

Other packages similar to music-metadata

node-id3

The node-id3 package is focused on reading and writing ID3 tags in MP3 files. It provides a simpler interface for handling ID3 tags compared to music-metadata, but it is limited to MP3 files and does not support other audio formats.

musicmetadata

The musicmetadata package is another tool for extracting metadata from audio files. It supports a variety of audio formats and provides similar functionality to music-metadata. However, it is less actively maintained and may not support the latest audio formats and tags.

id3js

The id3js package is a JavaScript library for reading ID3 tags from MP3 files. It is designed to work in both Node.js and browser environments. While it offers similar functionality to music-metadata for MP3 files, it does not support other audio formats.

README

music-metadata

Stream and file based music metadata parser for node.js. Supports any common audio and tagging format. TypeScript definitions are included.

Features

Support for audio file types

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

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

Compatibility

The JavaScript in runtime is compliant with ECMAScript 2017 (ES8). Requires Node.js® version 6 or higher.

Browser Support

Although music-metadata is designed to run the node.js. music-metadata-browser can be used on the browser side.

To avoid Node fs dependency inclusion, you may use a sub-module inclusion:

import * as mm from 'music-metadata/lib/core';

function	music-metadata	music-metadata/lib/core
parseBuffer	✓	✓
parseStream *	✓	✓
parseFromTokenizer	✓	✓
parseFile	✓

Sponsor

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Usage

Installation

Install using npm:

npm install music-metadata

or using yarn:

yarn add music-metadata

Import music-metadata

Import music-metadata in JavaScript:

const mm = require('music-metadata');

This is how it's done in TypeScript:

import * as mm from 'music-metadata';

Module Functions

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

1. Audio (music) files can be parsed using direct file access using the parseFile function
2. Using Node.js streams using the parseStream function.

Direct file access tends to be a little faster, because it can 'jump' to various parts in the file without being obliged to read intermediate data.

parseFile function

Parses the specified file (filePath) and returns a promise with the metadata result (IAudioMetadata).

parseFile(filePath: string, opts: IOptions = {}): Promise<IAudioMetadata>`

Example:

const mm = require('music-metadata');
const util = require('util');

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

parseStream function

Parses the provided audio stream for metadata. It is recommended to provide the corresponding MIME-type. An extension (e.g.: .mp3), filename or path will also work. If the MIME-type or filename (via fileInfo.path) is not provided, or not understood, music-metadata will try to derive the type from the content.

parseStream(stream: Stream.Readable, fileInfo?: IFileInfo | string, opts?: IOptions = {}): Promise<IAudioMetadata>`

Example:

const mm = require('music-metadata');

(async () => {
  try {
    const metadata = await mm.parseStream(someReadStream, {mimeType: 'audio/mpeg', size: 26838});
    console.log(metadata);
  } catch (error) {
    console.error(error.message);
  }
})();

parseBuffer function

Parse metadata from an audio file, where the audio file is held in a Buffer.

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

Example:

(async () => {
  try {
    const metadata = mm.parseBuffer(someBuffer, 'audio/mpeg');
    console.log(metadata);
  } catch (error) {
    console.error(error.message);
  }
})();

parseFromTokenizer function

This is a low level function, reading from a strtok3 ITokenizer interface. music-metadata-browser is depended on this function.

This also enables special read modules like:

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

orderTags function

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

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

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 * as mm from 'music-metadata';

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

Options

• duration: default: false, if set to true, it will parse the whole media file if required to determine the duration.
• observer: (update: MetadataEvent) => void;: Will be called after each change to common (generic) tag, or format properties.
• skipCovers: default: false, if set to true, it will not return embedded cover-art (images).
• skipPostHeaders? boolean default: false, if set to true, it will not search all the entire track for additional headers. Only recommenced to use in combination with streams.
• includeChapters default: false, if set to true, it will parse chapters (currently only MP4 files). experimental functionality

Although in most cases duration is included, in some cases it requires music-metadata parsing the entire file. To enforce parsing the entire file if needed you should set duration to true.

Metadata result

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.

mm.parseStream(someReadStream, {mimeType: 'audio/mpeg', size: 26838}, {duration: true})
  .then( function (metadata) {
     console.log(util.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:

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

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

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

   2. Use async/await

      Use async/await

      const mm = require('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 mm.parseFile(audioFile);
              // Do great things with the metadata
          }
      }
      

   3. Use a specialized module to traverse files

      There are specialized modules to traversing (walking) files and directory, like walk.

Licence

The MIT License (MIT)

Copyright © 2022 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.