Is the conversion done locally?

Yes, all processing happens in your browser. JSON files are never uploaded to a server, maximizing your privacy.

Is the conversion free?

Completely free, no registration required, no watermark, files up to 50 MB each. All processing is done in the browser.

Does it work on mobile browsers?

Yes, the tool is built entirely with HTML5/JS and runs smoothly on iOS Safari and Android Chrome.

Can I batch convert multiple JSON files to LRC?

Yes. Drag multiple JSON files onto this page — they will enter the workspace batch tool together with LRC pre-selected, and convert all at once. For converting entire folders, use the batch converter page.

Is my data private and secure?

Completely safe. All processing is done client-side in the browser. Subtitle files are never uploaded to any server — your content stays entirely on your local device.

Besides LRC, what other formats can I convert JSON3 to?

In the workspace, JSON files can also be converted to SRT, VTT, ASS, TXT, and TTML formats. Upload a JSON file and select the target format in the Convert tool.

YouTube JSON3 to LRC Lyrics Converter

Fast. Private. Perfect.

100% local processing in your browser. No upload. No waiting.

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JSON

{
  "events": [
    { "tStartMs": 1000, "dDurationMs": 3000,
      "segs": [{ "utf8": "Hello, world!" }] },
    { "tStartMs": 4500, "dDurationMs": 3500,
      "segs": [{ "utf8": "This is a subtitle file." }] }
  ]
}

LRC

[00:01.00]Hello, world!
[00:04.50]This is a subtitle file.
[00:08.50]Converted locally!

Drag & drop your JSON file here

or click to browse

Supports .json files up to 50 MB

100% LocalNo UploadSecureInstant

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How It Works

Upload JSON File

Drag & drop or select your .json file

Convert Instantly

We process it locally in your browser

Download LRC

Get your .lrc file immediately

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Why Choose AllSubConverter?

Your Privacy Matters

Everything runs in your browser. Your files are never uploaded.

Lightning Fast

Optimized processing engine converts files in seconds.

Free & Local

Each file can be up to 50 MB. Batches can contain up to 200 files or 1 GB total.

Works Everywhere

Works on Windows, Mac, Linux, iOS, Android - any modern browser.

About JSON to LRC

YouTube's timedtext API serves captions in JSON3 format — a JSON structure with an events array where each event carries a tStartMs timestamp and segs text fragments. This tool parses the JSON3 structure, extracts each event's start time and text, and outputs standard [MM:SS.xx] LRC lyrics usable in foobar2000, AIMP, Poweramp and other music players.

Input Format

JSON

JSON3 is YouTube's internal subtitle format, exported via the timedtext API. The file is a JSON object with an events array. Each event has tStartMs (start millisecond), dDurationMs (duration in ms), and segs (an array of text fragments, each with a utf8 field). Users typically download this format using youtube-dl, yt-dlp, or similar tools.

Output Format

LRC

LRC (.lrc) is a synchronized lyrics format that displays text line-by-line in music players. Each line begins with a [MM:SS.xx] time tag and does not store an end time — the player automatically advances to the next line.

Features

Automatically parses YouTube JSON3 events array and segs text fragments

Converts millisecond timestamps to precise LRC [MM:SS.xx] format

Output compatible with foobar2000, AIMP, Poweramp, MiniLyrics

Client-side processing — your files never leave your device

Supports UTF-8 encoding for CJK and non-Latin characters

Pure browser-based — no upload, complete privacy protection

Free to use, no signup, no watermark, files up to 50 MB each

Why Convert?

YouTube auto-captions downloaded via yt-dlp come as JSON3, but music players need LRC to display synced lyrics.

JSON3 is YouTube's proprietary format that only YouTube-related tools can parse; LRC is a universal lyrics standard supported by virtually every player.

JSON3 contains dDurationMs duration data, but LRC only needs start times — the converted file is simpler and cleaner.

Music players like foobar2000, Poweramp, and Musicolet cannot read JSON3 and require LRC for synchronized lyrics display.

After extracting audio from a YouTube music video, you need to convert the JSON3 subtitles to LRC for synced lyrics in audio players.

Language learning apps that show synced lyrics during audio playback expect LRC format, not YouTube's JSON3.

Discord music bots and streaming overlays use LRC to display lyrics during playback and do not support JSON3.

Format Differences

JSON3 uses tStartMs integer milliseconds; LRC uses [MM:SS.xx] time tags

JSON3 is structured JSON data; LRC is plain text with time prefixes

JSON3 stores duration and text fragment arrays; LRC only stores start time and single-line text

JSON3 is YouTube-proprietary; LRC is a universal lyrics standard

JSON3 is designed for YouTube's video system; LRC is designed for music players

JSON3 files are typically larger (JSON overhead); LRC is more compact and efficient

Common Use Cases

YouTube Music Lyrics Extraction

YouTube auto-captions download as JSON3, but music players need LRC. Convert JSON3 to LRC to turn YouTube subtitles into synced lyrics for foobar2000, AIMP, and Poweramp.

yt-dlp Subtitle to Lyrics

YouTube subtitles downloaded with yt-dlp are typically JSON3 format. Convert JSON3 to LRC to reuse them as synced lyrics in any audio player.

Language Learning Materials

JSON3 subtitles from YouTube educational videos can be converted to LRC for language learning apps that show synced text during audio playback.

Discord Bot Lyrics

Discord music bots use LRC format to display synced lyrics during playback. Convert YouTube JSON3 subtitles to LRC to integrate with your bot.

Mobile Music Players

Most mobile music players support LRC synced lyrics. Convert JSON3 subtitles downloaded from YouTube to LRC for use in iOS and Android music apps.

Related Formats

LRC (Lyrics)

Output format — a synchronized lyrics format with [MM:SS.xx] timestamp tags, used by music players like foobar2000, AIMP, Poweramp, and MiniLyrics.

JSON (YouTube JSON3)

Input format — YouTube's timedtext API subtitle format with events array and segs text fragments. Convert JSON3 to LRC to reuse YouTube subtitles as lyrics.

SRT (SubRip)

Universal subtitle format. If you need video player subtitles instead of music player lyrics, convert JSON3 to SRT in the workspace.

Frequently Asked Questions

What is YouTube JSON3 format?

JSON3 is YouTube's internal subtitle format. It is served via the timedtext API as a JSON object with an events array. Each event has tStartMs (start millisecond), dDurationMs (duration in ms), and segs (text fragments array, each with a utf8 field).

Can the converted LRC lyrics scroll in foobar2000 or mobile music players?

Yes. The generated LRC fully complies with the standard specification. With foobar2000 (ESLyric), AIMP, Poweramp, and similar players, name the lyrics file the same as the audio file to enable scrolling display.

What happens to timing-only events without segs?

Some events in YouTube JSON3 contain only timing information (like aAppend markers) without text fragments. These events are automatically skipped during conversion and do not affect the LRC output.

How do I download YouTube subtitles as JSON3?

Use yt-dlp: yt-dlp --write-auto-sub --sub-format json3 <video-URL>. The downloaded .json3 file can be directly imported into this tool. You can also fetch it via the YouTube timedtext API in a browser.

How are the segs text fragments in JSON3 handled?

The multiple utf8 text fragments in each event's segs array are automatically concatenated into a single LRC lyrics line. For example, two fragments "Hello " and "world" are merged into "Hello world".

What is LRC format?

LRC is a lyrics file format that uses time tags to synchronize text with music playback. Each line starts with a [MM:SS.xx] timestamp.

Ready to convert your subtitles?

Drop your JSON file here and convert to LRC instantly.

Convert YouTube JSON3 Subtitles to SRT, VTT, or LRC | AllSubConverter

Download YouTube captions as JSON3 and convert them to SRT, VTT, or LRC. Step-by-step guide covering yt-dlp, the JSON3 format, and free online conversion.

Aug 10, 20264 min read

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