Wyvek
Creator Tools

Subtitle Quality Checker & Optimizer

Check SRT reading speed, timing, line length & safe fixes.

Check your SRT before publishing

Find hard-to-read captions, timing problems, and awkward line breaks. Safe fixes never rewrite your words or timestamps.

Subtitle QA for short video, social clips, and web video

Auto captions can be technically valid while still being uncomfortable to read. A subtitle may disappear too quickly, contain an extremely long line, overlap the next cue, or break a sentence in a visually awkward place. This checker turns those problems into a review list before you publish.

What Safe Fixes will — and will not — change

Safe Fixes normalize repeated whitespace and rebalance line breaks when the same wording can fit inside the selected two-line limit. They never shorten dialogue, invent text, or move timestamps. Problems such as high CPS, overlaps, and very short cues are reported for review because automatically changing timing can desynchronize captions from the audio.

Short video preset vs delivery specifications

The Short Video preset is deliberately practical rather than platform-branded: 32 characters per line, two lines, and 20 CPS as a mobile-first starting point. It is not an official TikTok, Instagram Reels, or YouTube requirement. For professional delivery, select Custom and enter the limits required by your client or platform.

Industry reference values

Netflix's public English timed-text guidance uses a 42-character line limit and a maximum of two lines; its English subtitle guide also lists reading-speed limits up to 20 characters per second for adult programs. Wyvek includes a Netflix English reference preset so creators can compare against a published professional baseline, but passing this checker does not guarantee acceptance by any platform.

Pair it with the SRT Script Aligner

If your auto-caption timestamps are good but the words are wrong, first use the SRT Script Aligner to rebuild the text from your correct script. Then run the corrected file through this optimizer to check CPS, line length, timing, and presentation before importing it back into your editor.

Frequently asked questions

What does the subtitle optimizer check?

It checks SRT cue timing, overlaps, characters per second (CPS), line length, line count, very short or long cues, tight gaps, empty cues, repeated spaces, and awkwardly unbalanced two-line captions.

Does it change subtitle timing automatically?

No. Safe Fixes only normalize whitespace and improve line wrapping where the same text can still fit within the selected line limits. Timing, cue numbers, and wording are preserved.

Are the Short Video limits official TikTok, Reels, or YouTube rules?

No. The Short Video preset is a practical Wyvek starting point for mobile-first captions. Platforms and clients can have different requirements, so use Custom when you have a specific delivery guide.

What is CPS in subtitles?

CPS means characters per second. It estimates how quickly a viewer must read a cue by dividing visible character count by the amount of time that cue stays on screen.

Why is 42 characters per line included as a reference?

Netflix publishes a 42-character-per-line limit for English timed text and a two-line maximum in its public style guides. Wyvek includes that as a reference preset, not as a guarantee of delivery approval.

Do you upload my subtitle file?

No. Parsing, checking, safe fixes, and downloads all run locally in your browser. Subtitle content is not sent to Wyvek, GA4, or an AI service.

SRT Script Aligner Fix auto-caption text with your correct script while keeping SRT timestamps. Readability Score Measure reading ease and estimated grade level. Remove Line Breaks Strip line breaks and extra whitespace from text. Text Diff Checker Compare two texts and highlight the differences.