id3v2

Fast and stable ID3 parsing and writing library for Go, based only on standard library.

It can:

• support ID3v2.3 and ID3v2.4 tags;
• parse and write tags;
• work with available encodings;
• set artist, album, year, genre, unsynchronised lyrics/text (USLT), comments and attached pictures;
• set several USLTs, comments and attached pictures;
• be used in multiple goroutines.

It can't:

• do unsyncronization;
• work with extended header, flags, padding, footer.

id3v2 is still in beta. Until version 1.0 the API may be changed.

If you want some functionality, that library can't do, or you have some questions, just write an issue. And of course, pull requests are welcome!

Installation

$ go get -u github.com/bogem/id3v2

Example of usage

package main

import (
	"fmt"
	"log"

	"github.com/bogem/id3v2"
)

func main() {
	// Open file and parse tag in it.
	tag, err := id3v2.Open("file.mp3", id3v2.Options{Parse: true})
	if err != nil {
 		log.Fatal("Error while opening mp3 file: ", err)
 	}
	defer tag.Close()

	// Read frames.
	fmt.Println(tag.Artist())
	fmt.Println(tag.Title())

	// Set simple text frames.
	tag.SetArtist("New artist")
	tag.SetTitle("New title")

	// Set comment frame.
	comment := id3v2.CommentFrame{
		Encoding:    id3v2.EncodingUTF8,
		Language:    "eng",
		Description: "My opinion",
		Text:        "Very good song",
	}
	tag.AddCommentFrame(comment)

	// Write it to file.
	if err = tag.Save(); err != nil {
		log.Fatal("Error while saving a tag: ", err)
	}
}

Read multiple frames

pictures := tag.GetFrames(tag.CommonID("Attached picture"))
for _, f := range pictures {
	pic, ok := f.(id3v2.PictureFrame)
	if !ok {
		log.Fatal("Couldn't assert picture frame")
	}

	// Do something with picture frame.
	// For example, print the description:
	fmt.Println(pic.Description)
}

Options

// Options influence on processing the tag.
type Options struct {
	// Parse defines, if tag will be parsed.
	Parse bool

	// ParseFrames defines, that frames do you only want to parse. For example,
	// `ParseFrames: []string{"Artist", "Title"}` will only parse artist
	// and title frames. You can specify IDs ("TPE1", "TIT2") as well as
	// descriptions ("Artist", "Title"). If ParseFrame is blank or nil,
	// id3v2 will parse all frames in tag. It works only if Parse is true.
	//
	// It's very useful for performance, so for example
	// if you want to get only some text frames,
	// id3v2 will not parse huge picture or unknown frames.
	ParseFrames []string
}

Work with encodings

id3v2 can encode and decode text of avaialble encodings (ISO-8859-1, UTF-16 with BOM, UTF-16BE without BOM, UTF-8). All strings of frames are always encoded with UTF-8.

For example, if you set comment frame with custom encoding and write it:

tag := id3v2.NewEmptyTag()
comment := id3v2.CommentFrame{
	Encoding:    id3v2.EncodingUTF16,
	Language:    "ger",
	Description: "Tier",
	Text:        "Der Löwe", // must be UTF-8 encoded
}
tag.AddCommentFrame(comment)

_, err := tag.WriteTo(w)
if err != nil {
	log.Fatal(err)
}

it will be automatically encoded with UTF-16BE with BOM and written to w.

By default, if version of tag is 4 then UTF-8 is used for methods like SetArtist, SetTitle, SetGenre and etc, otherwise ISO-8859-1.

Documentation

https://godoc.org/github.com/bogem/id3v2