Subtitles rewriter

Subtitles Rewriter

What This Skill Does

Reformats and rewrites subtitle text for timing, readability, and on-screen clarity, following broadcast subtitle standards.

When To Use This Skill

• Auto-generated subtitles contain transcript errors that need correcting before delivery
• Subtitle timing needs reformatting for broadcast delivery (line length, reading speed, two-line breaks)
• Subtitles were originally written for one platform and need reformatting for another (cinema, broadcast, streaming, DVD)
• Foreign-language dialogue subtitles need to be adapted for clarity and reading speed without re-translating

What You Need To Provide

Required: The subtitle text to be rewritten; the context (documentary title, type of content — dialogue, narration, foreign language, on-screen text); the target platform (broadcast, streaming, cinema, DVD/home video) Optional: The original timecodes if reformatting is needed; the target maximum characters per line; the target maximum words per second (reading speed); whether this is SDH (subtitles for deaf and hard of hearing) or standard subtitles; the language

How the Assistant Approaches This

1. Reviews the existing subtitle text for transcript accuracy, line breaks, and character count — identifies errors and over-long lines
2. Reformats to the target platform's line length and reading speed standards (see Output Format for typical values)
3. Corrects errors in auto-generated transcript (common patterns: homophones, proper nouns misread, non-standard accents misread, punctuation errors)
4. For two-line subtitles, applies grammatical line-break rules — breaks at clause boundaries, not in the middle of phrases

Output Format

Corrected subtitle text in the format provided (SRT, WebVTT, or plain numbered blocks). Each subtitle block: number, timecode (preserved or adjusted if requested), two lines maximum, maximum 42 characters per line (broadcast standard), maximum 17 words per second reading speed. For plain text input without timecodes: numbered blocks only, with notes on any corrections made. Corrections are listed separately in a Changes Log at the end.

Platform standards applied by default unless otherwise specified:

• Broadcast (UK/international): 42 chars/line, 2 lines max, ~160–180 wpm reading speed
• Streaming (Netflix/Amazon standard): 42 chars/line, 2 lines max, 17 wpm max
• Cinema (DCP): 32–40 chars/line, 2 lines max, conservative reading speed

Quality Criteria

• No subtitle block exceeds the platform's character-per-line limit
• Line breaks occur at grammatical boundaries — not mid-phrase
• Reading speed is within platform standards — no subtitle requires faster-than-standard reading
• Proper nouns, technical terms, and names are corrected where auto-generation has produced errors
• Changes Log accurately records every correction made

Example

Input

Platform: Broadcast (UK standard) Content: Documentary interview — foreign language dialogue (French), English subtitles Context: Interview with a marine biologist discussing ocean pollution

Auto-generated subtitles (with errors):

1
00:02:14,400 --> 00:02:18,900
the microplastics they are entering the food chain at every level but we don't see them

2
00:02:19,200 --> 00:02:24,800
the fish consume them and then we consume the fish and nobody is talking about the concentration levels that we are now measuring in human blood samples

3
00:02:25,100 --> 00:02:27,300
it's not a projection anymore it's already happening

4
00:02:31,000 --> 00:02:37,200
in 1972 the scientist jock cousteau already described the Mediterranean as a garbage dump nobody listened

5
00:02:37,500 --> 00:02:42,100
and now here we are fifty years later and the situation is categorically worse not better

Output

1
00:02:14,400 --> 00:02:18,900
Microplastics are entering the food chain
at every level. We don't see them.

2
00:02:19,200 --> 00:02:22,600
The fish consume them,
and then we consume the fish.

3
00:02:22,700 --> 00:02:24,800
Nobody is talking about the concentration levels
we're now measuring in human blood samples.

4
00:02:25,100 --> 00:02:27,300
This isn't a projection anymore.
It's already happening.

5
00:02:31,000 --> 00:02:34,800
In 1972, the scientist Jacques Cousteau
described the Mediterranean as a garbage dump.

6
00:02:34,900 --> 00:02:37,200
Nobody listened.

7
00:02:37,500 --> 00:02:42,100
Fifty years later, the situation
is categorically worse. Not better.

---

Changes Log

Block	Change	Reason
1	Added capitalisation; restructured from run-on	Broadcast standard; readability
2	Split from original block 2; shortened each line	Original block 2 was over 180 words per minute at this timecode; split into two subtitles with adjusted timecodes
3	New block from end of original block 2	Overflow from split above
4	"it's not a projection anymore" → "This isn't a projection anymore"	Cleaner register for subtitle reading; subject pronoun added for clarity
5	"jock cousteau" → "Jacques Cousteau"	Proper noun correction — auto-generation phonetic error
5	Split into two blocks	Original block 5 was 22+ seconds with ~190 wpm; split required
6	"Nobody listened" separated as standalone block	Creates emphasis; fits naturally after the Cousteau subtitle
7	"here we are fifty years later" → "Fifty years later"	Reduced characters; removes register-inappropriate colloquial phrase for subtitle context

Known Limitations

• This skill corrects subtitle text based on the input provided. If the underlying transcript is wrong (mis-heard speech, incorrect translation), the skill corrects formatting errors but cannot know the content error. Provide accurate transcript text as input.
• Timecode adjustment (when a subtitle block is split or merged) is provided as a best estimate based on the text length. Precise timecodes must be confirmed against the actual audio in a subtitle editing application.
• Subtitle standards vary by broadcaster, territory, and platform. The defaults used here are broadcast-standard UK/international. Different platforms (Netflix, Amazon, Disney+) have specific style guides that may differ in small but delivery-critical ways — check the commissioning platform's technical specification before final delivery.
• SDH subtitles (including sound effects, music descriptions, and speaker identification) have different requirements that are not fully addressed by this skill's standard output. Flag SDH content explicitly when requesting a rewrite.

Related Skills

• rough-cut-notes
• press-kit-generator
• narrator-voice-adapter