Validation: Format, size (max 500 MB / 750 MB for dev), and duration (max 30 min / 60 min for dev) are checked before analysis. No minutes are deducted if validation fails.
UI: Progress indicator during upload. The editor is locked during analysis. The video loads into the player automatically when ready.
5.2 Trimming
Select a segment to keep (green) or remove (red).
Recommendation: Trim before AI processing to save time and minutes.
Drag handles for instant visual preview.
The trim must keep at least 5 s, otherwise Confirm stays disabled.
While playing, the handle you used last acts as the playhead – it settles there as your trim point when you pause. The subtitle buttons jump to the start, or the end, of the subtitle depending on the active handle.
6. AI Tools
6.1 Language Detection & Transcription
Automatic language detection after upload (the source language can also be set manually in the panel).
Two-step AI processing: transcription (Deepgram – word-level accuracy) → refinement (Gemini – formatting and correction).
After generation, a green code of the detected language appears next to the video, e.g. [hu].
Word-level timestamping ensures precise timing – no manual time adjustment needed.
50+ target languages supported.
A custom subtitle processor assembles subtitles according to readability rules.
6.2 Automatic Summary
After subtitle generation, the app creates an AI summary of the video content.
6.3 Profile Editor
Intelligent profiles automatically adjust subtitle appearance based on video aspect ratio.
3 built-in profiles: Standard (16:9), Reels/TikTok (9:16), Square (1:1).
Auto-detected but manually switchable.
7. Subtitle Editor
The editor is organized into panels accessible from the floating toolbar.
7.1 Timeline
Visual display of all subtitles on a timeline.
Playhead (red line): Shows current video position.
Controls: Zoom in/out, play/pause.
Navigation: Click a subtitle in the list (left panel) to jump to its time. Use "Previous" / "Next" buttons to browse subtitles.
Split: Double-click a subtitle on the timeline to split it into two.
Delete: Cross button in the top-right corner of a segment.
Add: "+" button inserts a new subtitle at the current time.
No manual timing needed – Deepgram word-level timestamping ensures accurate synchronization. The subtitle processor assembles subtitles automatically.
7.2 Style Settings
Text: Font selection (Google Fonts), color (palette), brightness, size.
Static background: The background stays visible between subtitles – its height follows the tallest subtitle and the text is centered inside it. Useful for covering original burned-in subtitles. In this mode the width is always full (dynamic width is disabled).
Real-time preview: Changes are instantly reflected in the player. Long subtitles wrap in a balanced way (no lone words on the last line).
7.3 Watermark
Toggle watermark on/off.
Position: 9 presets (corners, edges, center).
Size: Percentage of video width.
Opacity & Margin.
Custom logo: Upload your own image or revert to the default SublyAI logo.
Brand protection: Watermark is forced visible when minutes are below 15.
7.4 Content Editing
Click a subtitle in the list (left panel) or directly on the video canvas to open the inline overlay editor.
The editor appears as a text input field positioned exactly where the subtitle sits on the video, matching its font, size, color, and background.
1:1 with the video (WYSIWYG): The editor renders the subtitle exactly like the final export – line breaks and appearance match the video precisely.
Auto-save: Changes are saved automatically 500 ms after you stop typing.
Enter (without Shift) saves and closes the editor. Escape closes without saving.
Shift+Enter inserts a manual (hard) line break.
Undo (button) or Ctrl+Z reverts the subtitle to its state before you opened the editor.
Video playback pauses automatically when editing and resumes when you close the editor.
7.5 Keyboard Shortcuts
Spacebar: Play / Pause
← / →: Jump to previous / next subtitle
PageUp / PageDown: Jump to top / bottom of the page
Shift+Enter: Manual line break (in the subtitle editor)
Ctrl+Z: Revert to the original subtitle (in the subtitle editor)
7.6 Karaoke Effect
What it is: Highlights words as they are spoken. Works for AI transcription, for AI translations, and for subtitles you upload yourself.
Where: Toolbar → Subtitle Settings → Karaoke tab.
Effects:
Highlight current word – only the word being spoken is colored.
Progressive highlight – everything from the start up to the current word is colored.
Box behind word – a colored box appears behind the current word. Its color, opacity and corner radius come from the Background settings; the full subtitle background is not drawn in this mode.
Highlight color: for the text effects (Highlight current word / Progressive highlight).
Timing for translations is estimated by spreading the target words over the rhythm of the original speech; for uploaded SRT/VTT it is spread evenly across each cue. Only projects saved before karaoke shipped will not have it, and they need a fresh upload.
8. Export & Formats
8.1 Video with Subtitles (Hardcoded)
Subtitles are burned into the video image.
Formats: MP4, WebM, MOV.
Resolutions: 480p, 720p, 1080p, 1440p, 2160p.
Quality: Original, Low, Balanced, High.
Progress bar with percentage display during rendering.
8.2 Clean Video (No Subtitles)
Export video with watermark only, without subtitles.
8.3 Subtitle Files
SRT / VTT: Download external subtitle files.
8.4 Upload Own Subtitles
If you already have subtitle files (.srt / .vtt) from another source, you can upload them directly – no AI processing needed.
When to use: You have existing subtitles and only need styling, watermark, export, or burn-in.
Where: In the import step, click "Upload own subtitles (FREE)" and select your .srt or .vtt file.
What happens: The app skips AI transcription entirely. Your subtitles are loaded as-is into the editor.
What you can still do: Edit text, change style/position, add watermark, adjust timing, trim video.
Cost: Free – no minutes consumed.
9. Minutes & Pricing
9.1 What is Free
Uploading own subtitles (.srt / .vtt).
Styling, watermark, and video export.
Clean video export (without subtitles).
9.2 What Costs Minutes
Only AI subtitle generation and transcription.
9.3 Deduction
Minutes are deducted only when AI successfully generates subtitles for a video.
9.4 Buying Minutes
You can purchase additional minutes from the Minutes & Billing page in your dashboard.
9.5 Refunds & Claims
Minutes are deducted only for successfully generated subtitles.
If generation fails due to a server-side technical error, no minutes are deducted.
If minutes are deducted unfairly, contact us via the "Report Bug" link in the app footer.
10. Validation & Limits
Production limits: 30 minutes duration, 500 MB file size.
Development limits: 60 minutes, 750 MB.
Validation: Input is validated immediately after upload. If the format or parameters do not meet requirements, the app notifies you before analysis. No minutes are deducted.
11. Support & Bug Reports
Use the "Report Bug" link in the app footer if you encounter an issue.
Describe the problem and optionally upload debug audio/video for analysis.
Use the same form to request a refund if minutes were deducted unfairly.
For general support, use the contact form at Dashboard → Support.