About

This tool transforms raw SubRip (.srt) subtitle text into a structured JSON object usable in web applications, custom video players, or data analysis pipelines. Unlike simple text converters, this engine parses the specific timecode format of SRT files and calculates the absolute duration in milliseconds for every entry.

Video developers often face the risk of malformed subtitle parsing leading to desynchronized captions. This tool mitigates that risk by strictly validating the Index → Timecode → Text sequence. It handles the mathematical conversion of timestamps (e.g., 00:01:23,500) into computable integers, allowing for precise synchronization logic in JavaScript or Python environments.

Formulas

The parser breaks down the SRT structure and converts the sexagesimal time format into a linear millisecond value using the following logic:

T_ms = h × 3600 + m × 60 + s × 1000 + ms

Where h is hours, m is minutes, s is seconds, and ms is milliseconds extracted from the SRT timecode string.

Reference Data

SRT Component	JSON Key	Data Type	Example Raw	Example Parsed
Sequence Index	id	Integer	1	1
Start Time	start	String	00:00:20,000	"00:00:20,000"
End Time	end	String	00:00:24,400	"00:00:24,400"
Duration (calc)	startMs	Integer	20000	20000
Content	text	String	Hello World!	"Hello World!"

Frequently Asked Questions

SRT files often contain basic HTML like italics or bold. By default, this converter preserves them within the JSON string. If you require plain text, you can use a post-processing regex in your application to strip tags.

The parser uses a robust block-scanning algorithm. If a specific subtitle block lacks a valid timestamp arrow (-->) or index, it is skipped/logged as an error, but valid blocks are still processed and returned in the JSON array.

Not directly. HTML5 elements require WebVTT (.vtt) format. This JSON output is intended for developers building custom video players (like React Player or Video.js custom implementations) where you need full programmatic control over subtitle rendering.

Yes. The entire conversion process occurs within your browser's memory using the FileReader API. No data is sent to any server, ensuring privacy for sensitive transcripts.