SSA to JSON Subtitle Converter

Quickly convert SubStation Alpha subtitles to Structured JSON locally in your browser. Timelines and subtitle content are never uploaded.

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What happens when converting SSA to JSON?

SubStation Alpha content is parsed into a unified millisecond timeline before being exported as Structured JSON. Valid timing and subtitle text are preserved.

JSON output gives every subtitle start_ms, end_ms, and text fields for further programmatic processing.

Complex ASS / SSA style tags and positioning are removed while visible text and timing are converted.

Format overview

About SSA and JSON subtitle formats

Learn what each file format is, how it is structured, where it is commonly used, and what to consider during conversion.

Source file format

SSA · SubStation Alpha

SSA, or SubStation Alpha, is a classic advanced subtitle format and the predecessor of ASS. It supports styling, positioning, and effects, with SubStation Alpha v4 being a common version.

File structure: SSA files use sections such as Script Info, V4 Styles, and Events. Subtitle events are normally stored in Dialogue lines, and classic v4 files commonly include a Marked field.
Common uses: SSA is often found in older subtitle-authoring software, legacy subtitle archives, early anime subtitle projects, and players that still support SubStation Alpha.
Conversion notes: SSA and ASS are related but not identical. Text and timing can be preserved when converting to simpler subtitle formats, while complex styles and effects normally cannot.

Target file format

JSON · Structured JSON

JSON, or JavaScript Object Notation, is a structured data-interchange format rather than one industry-standard subtitle specification. Explicit fields can represent timing, text, and extensible metadata.

File structure: This tool uses a JSON object containing a cues array. Each cue has start_ms, end_ms, and text fields representing the start time, end time, and subtitle text.
Common uses: JSON is useful for subtitle software development, API exchange, batch processing, data analysis, automation, and preserving structured subtitle data for later programmatic or AI processing.
Conversion notes: Subtitle JSON schemas vary between applications. This tool can read subtitle arrays and objects containing cues or subtitles arrays, and it exports a consistent cues structure.