Subtitle Tool Guide

The subtitle tool lets you parse, convert, repair, and validate subtitle files entirely in your browser. No uploads — everything runs client-side.

Import & Parse

1. Choose a framerate — the framerate selector at the top determines how timestamps map to frame numbers. Pick the framerate that matches your video (e.g. 23.976 for most film, 25 for PAL broadcast, 29.97 for NTSC).
2. Paste or upload — paste subtitle text directly or drag-and-drop a file. The tool auto-detects the format (SRT, VTT, ASS, etc.).
3. Review the parse — entries appear in the preview pane with their timecodes and text. Any parse warnings show inline.

Operations

Enable any combination of operations before clicking Process. They run in a defined order regardless of toggle sequence.

Shift Timecodes

Move all timestamps forward or backward by a fixed offset.

Before: 00:01:00,000 → 00:01:03,000 Hello world After (shift +500ms): 00:01:00,500 → 00:01:03,500 Hello world

Remove Empty Subtitles

Delete entries with blank or whitespace-only text and reindex.

Strip Formatting

Remove all HTML tags and SSA/ASS override codes, keeping only plain text.

Before: <i>Hello</i> <b>world</b>After: Hello world

Enforce Minimum Duration

Extend short subtitles so they display for at least the specified duration.

Before: 00:01:00,000 → 00:01:00,200 Quick flash After (min 500ms): 00:01:00,000 → 00:01:00,500 Quick flash

Enforce Maximum Duration

Truncate long subtitles so they don't exceed the specified duration.

Enforce Minimum Gap

Ensure a minimum time gap between consecutive subtitle entries.

Merge Identical Consecutive

Combine adjacent entries with identical text into a single longer entry.

Before:00:01:00,000 → 00:01:02,000 Hello 00:01:02,000 → 00:01:04,000 Hello After:00:01:00,000 → 00:01:04,000 Hello

Framerate Conversion

Recalculate all timings from one framerate to another. Converts through frame numbers to avoid float errors.

Remove Hearing-Impaired Text

Strip SDH annotations ([MUSIC], (CRYING)), speaker labels (JOHN:), and music note lines.

Before: [MUSIC PLAYING] ♪ La la la ♪After: (entry removed — music-only)

Fix Unbalanced Tags

Balance unclosed/orphaned formatting tags and normalize self-closing variants like <i/>.

Bridge Gaps

Extend subtitle end times to close small gaps between consecutive entries.

Split Long Lines

Break lines exceeding the CPL limit at the best split point.

Before: This is a very long subtitle line that exceeds the character limitAfter:This is a very long subtitle linethat exceeds the character limit

Change Casing

Convert subtitle text to the selected case style (sentence, lower, upper, title) while preserving formatting tags.

Normalize Continuation Style

Add or remove continuation markers (... or -) between multi-entry sentences.

Normalize Dialog Dashes

Standardize dialog dash characters (hyphen, en-dash, em-dash) across all dialog entries.

Batch Search & Replace

Find and replace text across all entries, with optional regex and case sensitivity. Supports multiple rules.

Speed Stretch

Scale all timings by a factor to match a different playback speed (e.g. 1.04 = 4% slower).

Export

1. Choose the output format from the dropdown (SRT, VTT, SBV, ASS, DFXP, SCC, Graphics STL, etc.).
2. Download the file or copy to clipboard.
3. Filenames default to the original name with the new extension.

Graphics STL + Images (ZIP)

Select Graphics STL + Images (ZIP) from the output format dropdown to generate a ZIP bundle for DVD/Blu-ray authoring. The bundle contains:

• A .stl manifest with SMPTE timecodes and image file references.
• One .png per subtitle entry, rendered with configurable resolution, font, and outline settings.

When this format is selected, a settings panel appears where you can configure the project name, resolution, font size, font family, video standard, and outline width.