CaptionStack
Private by design

JSON TO SBV

JSON to SBV.

Convert JSON (.json) subtitles to YouTube SBV (.sbv) in seconds. No upload, no sign-up, nothing leaves your browser.

SRTVTTSBVLRCTTMLJSONCSVTXT
1

Choose your caption file

We’ll detect the format automatically. Drop several files to convert them all at once.

Don’t have a file handy?
2

Choose an output format

Select what you need on the other side.

100% privateYour files never leave this device.
8 formatsBuilt for the caption formats you use.
No limitsConvert as often as you need.

How to convert JSON to SBV

  1. Drop your .json file into the converter above, or click to browse. Several files at once become a ZIP.
  2. Check the quality report and fix timing or text in the editor if you need to.
  3. SBV is already selected as the output format. Click Download converted file.

Conversion happens entirely in your browser. Nothing is uploaded, no account is needed, and there is no file count limit.

About JSON (.json)

JSON is the easiest format to consume from code. CaptionStack reads an array of cue objects or an object with a cues array, accepts timestamps as milliseconds or time strings, and writes a versioned document with millisecond start and end values so you can load captions straight into a web app, database, or analytics pipeline.

About YouTube SBV (.sbv)

SBV files come from YouTube’s caption editor and its legacy download option. Each cue is just a timing line such as 0:00:01.000,0:00:04.200 followed by the text, with no sequence numbers or header, which makes them small but poorly supported outside YouTube.

What changes when converting JSON to SBV

SBV stores timing and text only, so converting to SBV drops cue identifiers. Converting from SBV is lossless.

Frequently asked questions

Is this JSON to SBV converter free?
Yes. CaptionStack is free and open source, with no limits on file count or conversions.
Are my caption files uploaded anywhere?
No. Parsing and conversion run in your browser using a local Web Worker. Your files never leave your device.
Can I edit the captions before exporting to SBV?
Yes. After import, open the editor to adjust start and end times, fix text, split, merge, or reorder cues. The quality report flags overlaps, short cues, and fast reading speeds with one-click fixes.
Can I convert many .json files to .sbv at once?
Yes. Drop multiple files and download all of the results as a single ZIP archive.

Other JSON conversions

Other ways to get SBV

All caption formats