What if the rewrite quality is poor?

Try a higher-quality model or clearer custom instructions. Very short or heavily colloquial text may need manual review after rewriting.

Is the AI Rewriter free?

The built-in tool is free to use; your AI provider may bill for API usage.

AI Subtitle Rewriter

Improve naturalness, fix grammar, shorten, expand, simplify, or rewrite subtitle text conversationally. Bring your own API key for OpenAI or an approved OpenAI-compatible provider.

Drag & drop your subtitle file here

Drag and drop subtitle files here or click to browse

SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI, TXT, JSON

AI Assisted · Cue Text Sent to Selected Provider

Core Processing Architecture

AI Rewrite Modes

Engineered for video editors and localization teams. Helps enforce common subtitle timing rules and formatting.

Improve Naturalness: make dialogue sound more fluent and natural.

Fix Grammar: correct grammar, spelling, and punctuation errors.

Shorten: condense verbose subtitles into concise, readable lines.

Expand: add natural wording to overly terse or clipped subtitles.

Simplify: rewrite using plainer language and shorter words.

Make Conversational: rewrite in a natural, spoken tone.

Custom: follow your own instructions for any rewriting task.

Choose a built-in OpenAI model or enter a custom model ID for an approved OpenAI-compatible endpoint.

For SRT and VTT output, timing and cue structure are retained while the text is rewritten.

Your API key stays in memory for the session and is saved on this device only after you choose Remember.

Live Preview & Execution Pipeline

AI Subtitle Rewriter Live Execution Demo

subtitles.srt

READYLive Editor

00:01.000Hello, world!00:04.500This is a subtitle file.00:09.120⚡ Realtime in-browser edit

Direct Provider Processing

File loading happens in your browser runtime; subtitle batches are sent directly to your chosen AI provider using your configured API key.

Millisecond Precision

Millisecond-accurate timecode parsing and arithmetic prevent synchronization drift across desktop and web players.

Fault-Tolerant Engine

Automatic multi-encoding detection and syntax sanitization gracefully handle malformed cues and unexpected linebreaks.

Production Workflows

Who Needs AI Rewriting?

Real-world scenarios across video post-production, course transcription, and global localization.

SCENARIO #1

Auto-Generated Captions

Improve speech-to-text captions that have awkward phrasing, missing punctuation, or run-on sentences.

SCENARIO #2

Translation Polish

Fix grammar and improve the natural flow of machine-translated subtitles before publishing.

SCENARIO #3

Accessibility Readability

Shorten overly long subtitle lines so they fit on screen and meet CPS readability standards.

SCENARIO #4

Content Summaries

Generate a concise text summary of a video's subtitle track for descriptions or metadata.

SCENARIO #5

Fansub & Localization

Expand terse translations into more natural, idiomatic subtitles for the target language.

SCENARIO #6

Educational Content

Improve the clarity and grammar of subtitles in lecture videos and online courses.

Execution Pipeline

How It Works

Streamlined end-to-end processing pipeline engineered for speed and precision.

STEP 01

Upload & Import

Upload your subtitle file.

PHASE 01

STEP 02

Format Analysis

Choose OpenAI or an approved OpenAI-compatible provider, then enter your API key.

PHASE 02

STEP 03

Choose a rewrite task

improve naturalness, fix grammar, shorten, expand, simplify, make conversational, or custom.

PHASE 03

STEP 04

Processing

Select an AI model based on your quality and cost preferences.

PHASE 04

STEP 05

Click Rewrite

Parsing happens locally, and cue text is sent in batches directly to your chosen provider.

PHASE 05

STEP 06

Delivery

Download the rewritten subtitle file in SRT, VTT, or TXT format.

PHASE 06

Engine Capabilities

Why Choose AllSubConverter?

Client-Side Privacy

Standard tools run in your browser so standard files are not uploaded to our servers.

Fast Local Parsing

Optimized processing engine parses and converts files directly in your browser.

Generous Batches

Up to 50 MB per file, 200 files or 1 GB total per batch.

Universal Compatibility

Runs in modern browsers across Windows, macOS, Linux, iOS, and Android.

Tool Suite

More Subtitle Tools

Subtitle Format Cleaner

Remove formatting, tags and noise

Subtitle Editor

Edit subtitle content and timings

Subtitle Sync & Timing Calibration

Adjust timing with millisecond precision

Subtitle Merger

Combine multiple subtitle files

AI Subtitle Translator

Translate to 19 built-in target languages

Frequently Asked Questions

Yes. The tool connects with your own API key. You can use OpenAI or an approved OpenAI-compatible endpoint. The key is kept in memory for the session and sent directly to your chosen provider, never to our servers.

Seven tasks: Improve Naturalness (make dialogue fluent), Fix Grammar (correct errors), Shorten (condense), Expand (add natural wording), Simplify (use plainer language), Make Conversational (spoken tone), and Custom (follow your own instructions).

For SRT and VTT output, timestamps and cue structure are retained while the text is rewritten. TXT output contains the rewritten text without timing.

Cost depends on your provider, model, and number of cues. Check the provider's current pricing before running a large subtitle file.

Parsing and output generation happen locally. Rewrite requests, including cue text and your API key, go directly from your browser to the provider you choose. We never see or store your files or key.

Input: SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI. Output: SRT, VTT, or TXT.

Ready to convert your subtitles?