Caption line breaks: Netflix bottom-heavy pyramid rule vs Sume cards

The rule

The Netflix English Timed Text Style Guide recommends line breaks that form a bottom-heavy pyramid when a caption runs to two lines, meaning the second line is the longer one. The guide pairs this with 42 characters per line and a limit of two lines.

The reason is readability: a longer top line pushes the eye across a wide span and then down, while a shorter top line feels balanced.

How Sume cards break

Sume's burned-in caption styles group words into phrase cards using design.phrasing: max_words, max_chars and pause_seconds. Cards are split by those settings and by pauses in speech, not by a pyramid rule. You can supply authored cues, where each cue's text may include a newline for a two-line card, which gives you exact control over where the break goes.

Writing pyramid breaks yourself

With authored cues you can apply the rule in code. Take the text, find the split nearest the middle that keeps the second line equal or longer, and prefer to break after punctuation or before a conjunction.

• If the whole phrase fits on one line of 42 characters, do not break it.
• Otherwise split near the middle and move the break so line two is at least as long as line one.
• Do not split names, numbers with units, or verbs from their particles where you can avoid it.
• Send the result as cues with a newline in text.

What to leave alone

The editorial-emphasis style is a deliberate design: its second line is a larger phrase-final word. That is a stylistic choice for ads and is not the Netflix convention. Do not compare it to the guide.

The aim here is a style rule, not a certification. If you deliver to a broadcaster, follow their spec and check with their tools.

A small helper to place the break

For a phrase of up to 84 characters, try every space as a break point and score it: line two must be at least as long as line one, neither line may exceed 42, and the difference in length should be small. Pick the lowest-scoring break and add a bonus when it follows a comma.

Run it over your cue list, send the result as cues, and keep the originals so you can compare the look against Sume's own grouping.

Takeaway

Sume decides breaks from speech and phrasing settings. If you want a bottom-heavy pyramid, write the cues yourself and pass a newline where each break goes.