GO SYLT

A pretty convenient CLI tool that reads and writes synced lyrics to MP3 files in SYLT (SYnchronized Lyrics/Text) format.

Features

• Supported input formats: LRC, SRT, and VTT
• Configurable language codes (case-insensitive 3-letter ISO 639-2 codes, e.g. eng, zho, und)
• Read and display existing SYLT lyrics from MP3 files
• Creates output files with " - sylt" suffix to preserve originals

Still, backing up originals is recommended.

Download

Visit the Releases page for pre-compiled binaries.

You can also build from source:

git clone https://github.com/mogita/go-sylt
cd go-sylt
go build

Usage

go-sylt [--lang <code>] <mp3_file> [lyrics_file]

Currently go-sylt supports ID3v2.3 and ID3v2.4 tags only. For MP3 files with older or unsupported ID3 versions, please convert them to a supported version first. You can use tools like Kid3 for this purpose.

Examples

# Write SYLT lyrics to MP3 file
./go-sylt song.mp3 lyrics.lrc

# Write lyrics and specify English language
./go-sylt --lang eng song.mp3 lyrics.srt

# Write lyrics using VTT format in Chinese
./go-sylt --lang zho song.mp3 subtitles.vtt

# Read existing SYLT lyrics from MP3 file and display
./go-sylt song.mp3

Language codes

--lang accepts any 3-letter ISO 639-2 code and is case-insensitive (ENG, Eng, and eng are all accepted and stored as eng). Common values:

• eng — English
• zho — Chinese
• jpn — Japanese
• kor — Korean
• spa — Spanish
• fra — French
• deu — German
• und — undetermined (default)

For the full list, see the ISO 639-2 language code list.

Output

The tool creates a new MP3 file with the same name as the input file but with " - sylt" appended before the extension. For example:

• Input: song.mp3 → Output: song - sylt.mp3

Encoding

When writing SYLT frames, go-sylt always uses:

• Text encoding: UTF-8 (ID3v2 encoding byte 0x03)
• Timestamp format: absolute milliseconds (0x02)
• Content type: lyrics (0x01)

This matches the format used by most modern players and avoids surrogate-pair pitfalls that affect UTF-16 handling. When reading SYLT frames, all four ID3v2 text encodings are supported (ISO-8859-1, UTF-16 with BOM, UTF-16 big-endian, UTF-8) so files written by other tools are readable.

If you need to write a non-UTF-8 SYLT frame, please open an issue describing your use case.

Credits

• github.com/bogem/id3v2/v2 - ID3v2 tag manipulation

Contributing

Contributions are welcome! Should you find any issues or have any suggestions, kindly submit an issue or PR with the provided templates. Thank you!

Development

• Go 1.21 or above
• golangci-lint for linting

# Run tests
go test -v

# Run linter
golangci-lint run

Releasing

Visit the Releases page, create a release on the main branch with a tag in the format of X.Y.Z or X.Y.Z-rc1. The workflow will automatically build and upload the binaries.

License

MIT © mogita