Subly: AI Subtitles & Captions

About Subly: AI Subtitles & Captions

Subly turns speech into subtitles right on your phone — no cloud, no uploads, no account. Import a video, get an accurate transcript in seconds, style the captions, and export a video with subtitles burned in.

Add subtitles to video offline. Transcribe speech to text in 100+ languages. Turn talking clips into captioned Reels, Shorts, Stories, TikToks, lessons, interviews and vlogs — most people watch with the sound off, and captions are what keeps them watching.

HOW TO ADD SUBTITLES TO A VIDEO
1. Import a video from your gallery, or share it into Subly from any app.
2. Subly transcribes the speech on device with Whisper AI.
3. Edit the text, fix the timing, pick a caption style.
4. Export a video with burned-in subtitles, or an SRT / VTT / TXT file.

100% ON-DEVICE, 100% PRIVATE
• Offline subtitle generator — after one model download, no internet needed
• Video and audio never leave your phone; nothing is uploaded to a server
• No sign-up, no login, no watermark on your exports
• Works on a plane, in the subway, on set

SPEECH TO TEXT IN 100+ LANGUAGES
• Automatic speech recognition powered by Whisper AI
• Auto language detection, or pick the spoken language for extra speed
• Word-level timing — every word synced to the video
• Pick your model: smaller for speed, larger for accuracy
• Long videos are fine, and transcription keeps running in the background

BILINGUAL SUBTITLES AND TRANSLATION
• Translate subtitles into another language while transcribing
• Show the original and the translation together, one line above the other
• Reach an international audience with the same clip

A REAL SUBTITLE EDITOR
• Edit any word; retime the start and end of every cue
• Split a cue at the playhead, merge cues, delete what you do not need
• Find and replace across the whole transcript
• A personal dictionary that fixes recurring names and terms automatically next time
• Speaker labels — NAME: on screen and in exported SRT/VTT
• Readability warnings when a line runs too fast or too long
• Undo and redo

CAPTION STYLES FOR SOCIAL VIDEO
• Ready-made caption templates, previewed live on your own video
• Karaoke word highlight — the spoken word lights up as it is said
• Animated captions: fade, rise, pop, bounce, typewriter, blur in, shake
• One-word-at-a-time mode for high-retention captions
• Fonts, colors, highlight colors, backgrounds: box, band, glass, glow, outline, soft shadow, accent plate
• Drag to place, pinch to resize anywhere in the frame
• Save your own look as a template and reuse it in every project

EXPORT ANYWHERE
• Burn subtitles into the video and save it to your gallery
• Choose resolution up to 4K, codec and frame rate
• Share the finished clip to TikTok, Instagram, YouTube or WhatsApp
• Export subtitle files: SRT and VTT
• Export the transcript as TXT or Markdown, or copy it to the clipboard

PROJECTS AND BATCHES
• Every video becomes a project you can reopen, restyle and export again
• Queue several videos and transcribe them one after another
• Trim first and transcribe only the part you need

Subly is an auto caption generator, video transcription app, subtitle maker, subtitle editor, SRT maker and offline speech-to-text notepad in one — for creators, editors, teachers, journalists, podcasters and anyone who needs subtitles fast.

The app speaks 34 languages. Free, with ads; an optional subscription removes them.

Questions or a feature request? Leave a review or write to us from the support page — we read everything.