Sub Editor

A fast, visual subtitle editor built for people who care about timing.

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Built by a subtitle editor, for subtitle editors

Sub Editor was born out of frustration. After years of doing subtitle work — manually scrubbing through video, counting characters by eye, and losing sessions to crashes — the tools available still felt like they were designed by engineers who had never actually sat down to subtitle a two-hour film.

So this was built from scratch, by someone who has. Every feature exists because it was genuinely needed. The waveform timeline so you can see the speech, not just guess at it. The character limit warnings because CJK and Latin text behave differently and no other tool tracks them separately. The pre-roll so you hear context before each block. The keyboard-first workflow because reaching for the mouse 400 times in a session adds up.

If you've ever:

• Placed a subtitle and had to rewatch the same 3 seconds five times to get the timing right
• Manually split a long line and recalculated the duration yourself
• Lost 20 minutes of work because the app didn't autosave

— this was made for you.

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Why Sub Editor?

Most subtitle tools force you to work blind — you type text into a table and guess at the timing. Sub Editor is built around a waveform timeline, so you can see exactly where speech starts and ends before you place a single block.

• Tired of manually counting characters for each subtitle? Sub Editor flags overlong lines automatically, with separate limits for CJK and Latin text.
• Tired of switching between a text editor and a video player to check your work? The subtitle overlay updates in real time as you scrub.
• Tired of losing work when the app crashes? Auto-save runs in the background every minute.

Sub Editor is for translators, video editors, and content creators who need to produce clean, well-timed subtitles — without fighting their tools.

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Interface

Video player with live subtitle overlay · Waveform timeline with subtitle blocks · List view with character limit warnings

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Features

Waveform Timeline	See audio peaks and subtitle blocks side by side. Drag, resize, and snap with precision.
Live Subtitle Overlay	Preview subtitles on the video as you edit — no separate preview window needed.
Smart List View	Click to edit inline. Pro-rata split (Enter) divides both text and duration at the cursor.
Dual-Language Support	Automatic CJK / Latin detection with independent character limit warnings per line.
Pre-Roll Playback	Plays back slightly before the target point so you hear context — no more replaying from the start.
Audio-Only Mode	Extract and play just the audio for tighter timing on music or fast speech.
Find & Replace	Regex-capable search across all subtitle text.
Session Restore	Playhead position and timeline zoom are saved with the project (.sep format).
Auto-Save & Recovery	Background auto-save every 60 seconds with crash recovery on next launch.

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Download & Install

Get the latest release from the Releases page.

macOS (Apple Silicon)

1. Download Sub-Editor-macOS-ARM.dmg
2. Open the DMG and drag Sub Editor into Applications
3. First launch: right-click the app → Open to bypass Gatekeeper

Windows (x64)

1. Download Sub-Editor-Windows.zip
2. Extract and run Sub Editor.exe — no installation required

Linux (Ubuntu / Debian)

1. Download Sub-Editor-Linux.deb
2. Install with:

   sudo apt install ./Sub-Editor-Linux.deb

3. Launch from your app menu or run sub-editor in terminal

All required libraries (libmpv, ffmpeg, xcb) are bundled. No extra packages needed.

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Running from Source

Prerequisites: Python 3.10+, uv, mpv, and FFmpeg

# macOS
brew install mpv ffmpeg

# Linux
sudo apt install libmpv-dev ffmpeg

git clone https://github.com/shfire616/Subtitle-Editor.git
cd Subtitle-Editor
uv run python src/main.py

uv handles the virtual environment and all Python dependencies automatically.

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Usage Guide

Opening a File

• Drag & drop a video or audio file onto the window
• Or use File → Open / Cmd+O
• If a .srt file with the same name exists in the same folder, it loads automatically

Timeline Editing

Action	How
Move a block	Drag the block body
Resize a block	Drag the left or right edge
Snap edge to playhead	Right-click the block edge
Split at playhead	Press S
Add blank block	Press D
Zoom	Ctrl+Scroll or Cmd/Ctrl + = / -

List View Editing

Action	How
Edit text	Left-click any text cell
Navigate rows	Arrow keys (playhead follows)
Split block at cursor	Enter inside text cell (text and duration split proportionally)
Merge with previous	Backspace at start of text
Merge with next	Delete at end of text

Exporting

• File → Export SRT or Cmd/Ctrl + E — exports the final .srt file
• File → Export Text — plain text, one line per subtitle

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Hotkeys

Key	Action
Space	Play / Pause
S	Split at playhead (Timeline)
D	Add blank subtitle at playhead
Enter	Pro-rata split (inside text cell)
Backspace	Merge with previous (cursor at line start)
Delete	Merge with next (cursor at line end)
Cmd/Ctrl + M	Merge selected blocks
Cmd/Ctrl + E	Export SRT
Cmd/Ctrl + F	Find & Replace
Cmd/Ctrl + S	Save project
Cmd/Ctrl + Z / Y	Undo / Redo
Cmd/Ctrl + A	Select all
Cmd/Ctrl + = / -	Zoom timeline in / out
T	Toggle list view
K / L	Decrease / increase playback speed

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License

GNU General Public License v3.0 — free to use, modify, and distribute. Derivative works must remain open source.