Auto-Merge Short Cues
Fast. Private. Perfect.
Combine fragmented subtitles from Whisper and YouTube into clean, readable cues. Stop the rapid-fire flashing of one-word subtitle blocks.
Drag & drop your subtitle file here
or click to browse
SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI, TXT
How It Works
Upload your subtitle file (especially effective on Whisper or YouTube output).
Set the merge thresholds: max characters per line, pause threshold, and max merged duration.
The merger scans for adjacent cues with short gaps and combines them greedily.
Each merge only happens if the combined text fits the character limit and duration cap.
Download the cleaned subtitle file with natural, readable cue blocks.
Why Choose AllSubConverter?
Your Privacy Matters
Everything runs in your browser. Your files are never uploaded.
Lightning Fast
Optimized processing engine converts files in seconds.
Truly Unlimited
No file size limits. No daily limits. Completely free.
Works Everywhere
Works on Windows, Mac, Linux, iOS, Android - any modern browser.
What the Auto-Merger Does
Who Needs Auto-Merging?
Whisper & AI Transcription
AI transcription tools fragment speech into tiny one-word cues that flash rapidly. Merge them into natural sentences automatically.
YouTube Auto-Captions
YouTube's automatic subtitles break text into very short blocks. Combine them for a smooth reading experience before publishing.
Post-Production Editing
Before editing or translating, merge fragmented cues so you work with complete sentences instead of fragments.
Accessibility & Reading Comfort
Rapid single-word subtitles are hard to read. Merging improves comprehension for all viewers.
Frequently Asked Questions
AI transcription tools like Whisper and YouTube auto-captions generate very short cues, often one or two words each, with tiny gaps between them. This causes rapid flashing on screen and poor readability.
No. Cues separated by pauses longer than your threshold are never merged. This preserves natural breaks where the speaker actually paused.
Input: SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI. Output: SRT.
It merges adjacent cues only when three conditions are met: the gap between them is shorter than your pause threshold (default 400ms), the combined text fits your character limit (default 35), and the merged duration stays under the maximum (default 5 seconds).
Only minimally. The merged cue keeps the first cue's start time and takes the last merged cue's end time. The on-screen timing stays accurate to the original speech.
Yes, completely free with no sign-up or limits. It runs entirely in your browser.