AI Subtitle Quality Control — Fix Issues Before You Publish
QC is the step most creators skip. VibeSubs scans every subtitle cue for timing gaps, overlaps between cues, characters-per-second (CPS) violations, and over-long lines — then offers one-click fixes so your subtitles meet platform standards.
How Subtitle QC Works
Three steps from upload to clean subtitles
Upload or translate subtitles
Upload an SRT, VTT, ASS, or SBV file directly, or run a translation first and open the QC panel on the result. No conversion or reformatting needed.
Run the QC scan
VibeSubs checks every cue against professional broadcast standards — timing gaps, overlaps between cues, CPS violations, over-long lines, and empty entries.
Review issues and apply fixes
Accept individual fixes cue by cue, or use auto-fix to apply all suggested corrections in one click. Pro plans include full auto-fix actions.
6 Things the QC Engine Checks
Every cue is scanned against professional broadcast standards
Detects gaps shorter than 83ms between cues that cause subtitle flicker on some players.
Flags cues whose end time extends into the next cue's start time.
Characters per second above 20 CPS makes subtitles unreadable — VibeSubs flags and can split or shorten affected cues.
Lines over 42 characters wrap awkwardly on mobile screens — the QC engine identifies and suggests splits.
Blank subtitle entries confuse players and waste runtime — caught and removed automatically.
Accept all suggested fixes in one click. Pro plans include auto-fix actions.
Why Subtitle QC Matters
YouTube, Netflix, and broadcast standards define strict CPS limits (17–20 CPS), minimum gap widths (2 frames), and maximum line lengths. Submitting subtitles that violate these specs causes rejections or poor viewer experience. VibeSubs QC runs these checks automatically so you don't have to.
Frequently Asked Questions
Everything you need to know about subtitle quality control
Characters per second (CPS) measures how fast viewers need to read a subtitle. The industry standard is 17 CPS for general audiences and up to 20 CPS for young adults. Higher values mean viewers cannot keep up with the text. VibeSubs flags cues that exceed 20 CPS and can split or shorten them automatically.
A gap below 83 milliseconds (2 frames at 24fps) between the end of one cue and the start of the next is too short for viewers to perceive as a pause. Some players flash the subtitle or skip it entirely. VibeSubs flags these gaps and offers to extend the first cue or add a small buffer.
Yes. QC runs on both original and translated subtitle files. It is especially important after translation because AI-translated text is often longer than the source, which can push a cue over CPS or line-length limits.
QC reports (showing all issues) are available on all plans. Auto-fix actions — one-click apply — are available on Pro and above plans.