English Closed Captioning Style Guide

Nov 25, 2024

10 min read

Closed captions are crucial for ensuring accessibility and maintaining professional quality in long-form video content. This guide details the fundamental principles to follow when creating English closed captions, including best practices for timing, readability, and style. At Fluen Studio, many of these rules are seamlessly embedded into our AI and NLP-powered algorithms, applying them automatically wherever possible to save you time and effort.

Throughout this guide, you’ll find clear examples and actionable guidelines tailored specifically for long-form content, helping you create captions that meet high industry standards. Whether you're new to captioning or looking to refine your process, this resource is designed to make closed caption creation more effective and straightforward.

1. Timing and Synchronization

Effective timing and synchronization are crucial for ensuring that subtitles enhance the viewing experience without distracting or confusing the audience. Proper synchronization aligns the subtitles seamlessly with the audio and visual elements of the content.

1.1 Minimum and Maximum Durations

Minimum Duration: Subtitles should remain on-screen for at least 5/6 of a second (approximately 20 frames at 24fps). This duration ensures that even fast readers have sufficient time to process the text. Shorter durations may cause viewers to miss information, leading to frustration and a diminished understanding of the content.

Maximum Duration: Subtitles should not exceed 7 seconds. Displaying subtitles for longer periods can lead to visual fatigue and redundancy, especially if the text does not change. Prolonged subtitles may also interfere with the viewer's focus on the visual content.

1.2 Synchronization Principles

Align with Speech Onset and End: Subtitles must appear synchronously with the speaker's dialogue. They should appear when the speaker begins talking and disappear when the speech concludes. Misalignment can confuse viewers, making it difficult to follow the conversation and detracting from the overall content.

Gaps Between Subtitles: Maintain a minimum gap of 1.5 seconds between subtitle events to ensure smooth transitions. This spacing prevents "stacking" subtitles, which can overwhelm the viewer and disrupt the viewing experience.

Best Practices:

Strategic Gaps: Use gaps to separate distinct dialogue or scenes, allowing viewers to process each subtitle without cognitive overload.
Avoid Overlap: Ensure that new subtitles do not appear too quickly after the previous ones, maintaining a comfortable reading pace.

Lag and Anticipation: Subtitles should neither anticipate speech by more than 1.5 seconds nor lag behind by more than 1.5 seconds. Proper timing ensures that subtitles align with the audio, enhancing comprehension.

Exceptions:

Off-Screen Narration or Voiceovers: Slight flexibility in timing is acceptable to accommodate the nature of the narration.

Pacing with Speech Speed: Match the pacing of the subtitles with the natural speed of the speech. For visible speakers, lip-syncing is essential as it reinforces understanding and maintains synchronization between audio and visual elements.

2. Readability: Line Length, Layout, and Character Limits

Ensuring readability is fundamental for effective subtitles. Proper line length, layout, and adherence to character limits make subtitles easy to read and understand.

2.1 Character and Line Limits

Characters per Line: Limit each line to a maximum of 42 characters, including spaces and punctuation. This constraint ensures that subtitles do not overwhelm the screen and remain legible.

Best Practices:

Conciseness: Use clear and concise language to convey the message within the character limit.
Avoiding Overcrowding: Prevent lines from becoming too dense, which can strain the viewer's eyes.

Lines per Subtitle: Restrict each subtitle to a maximum of 2 lines. Limiting the number of lines per subtitle prevents overcrowding and maintains visual clarity.

2.2 Placement

Subtitles should be center-justified and placed at the bottom of the screen. This standard positioning ensures consistency and minimizes interference with the visual content.

Exceptions:

Important Visuals: If essential elements like lower-thirds, graphics, or on-screen actions occupy the bottom area, consider placing subtitles at the top of the screen to avoid obstruction.

2.3 Text Breaks and Line Segmentation

Proper segmentation enhances the readability and flow of subtitles. Breaking lines appropriately ensures that viewers can follow the dialogue without confusion.

Guidelines for Line Breaks:

After Punctuation Marks: Preferably, break lines after commas, periods, and other punctuation to maintain natural pauses.
Avoid Separating Words Unnaturally:
- Articles and Nouns: Do not split articles (a, an, the) from nouns. (e.g., "the pencil" instead of "the / pencil")
- Prepositions and Objects: Keep prepositions with their objects. (e.g., "on the couch" instead of "on / the couch")
- Conjunctions and Clauses: Do not separate conjunctions from their clauses. (e.g., "and those books" instead of "and / those books")
- Nouns and Adjectives: Keep descriptive pairs together. (e.g., "a small bird" instead of "a / small bird")
- Names: Do not split names. (e.g., "Joe Smith" instead of "Joe / Smith")
- Verbs and Auxiliaries: Keep verbs with their auxiliary verbs. (e.g., "has eaten" instead of "has / eaten")

Example: INCORRECT

We are trying to get a

smooth subtitle line.

CORRECT

We are trying to get

a smooth subtitle line.

Best Practices:

Natural Flow: Ensure that line breaks do not disrupt the natural reading flow.
Clarity: Maintain clarity by keeping related words and phrases together.
Visual Balance: Distribute text evenly across lines to enhance visual appeal.

3. Dialogue, Interruptions, and Speaker Changes

Handling dialogue, interruptions, and speaker changes effectively in subtitles ensures that the conversation's dynamics are accurately conveyed to the viewer.

3.1 Speaker Differentiation

Using Hyphens for New Speakers: Use a hyphen (-) to indicate a change in speakers within subtitles. This method clearly distinguishes different speakers, especially in rapid exchanges.

Example Cue 1:

- Are you coming? Example Cue 2:

- In a minute.

Multiple Speakers in One Subtitle: When multiple speakers appear within a single subtitle, ensure that each line represents a distinct sentence or complete thought. This clarity prevents confusion about who is speaking and maintains the flow of the conversation.

Example:

- Are you okay?

- Yes, just a scratch.

3.2 Sound Effects and Speaker Labels

Sound Effects: Use brackets to denote sound effects within subtitles. This practice differentiates non-dialogue sounds from spoken words, providing context without confusion.

Example:

[phone ringing] [door slams]

Simultaneous Effects and Dialogue: When sound effects occur simultaneously with dialogue, use hyphens to differentiate between the two.

Example:

- [dog barking] - It's just the neighbor's dog.

Whispers and Speaker Labels:

Whispered Dialogue: Enclose whispered dialogue in brackets to indicate a softer tone, helping viewers understand the delivery's subtleness.

Example:

[whispering] I'll see you tomorrow.

Speaker Names: Include speaker names when necessary, especially in scenes with multiple characters or when the speaker is off-screen. This addition provides clarity about who is speaking.

Example:

- [Kim] Are you coming?

- [John] In a minute.

3.3 Interruptions

Using Double Hyphens for Abrupt Interruptions: Use double hyphens (--) to represent abrupt interruptions in dialogue. This notation conveys the sudden stop or change in the conversation.

Example:

I told you-- Stop it!

Best Practices:

Clarity: Ensure that interruptions are clear and do not disrupt the readability of the subtitle.
Consistency: Use the same notation for all types of interruptions throughout the content.

4. Punctuation and Formatting Rules

Proper punctuation and formatting in subtitles enhance readability and ensure that the intended meaning is conveyed accurately.

4.1 Sentence Continuation Across Subtitles

Avoiding Ellipses for Seamless Continuation: Do not use ellipses (...) for sentences that continue naturally into the next subtitle. Allow the text to flow without unnecessary punctuation, maintaining the sentence's integrity.

Example: INCORRECT

I was thinking......

we could go together.

CORRECT

I was thinking

we could go together.

When to Use Ellipses: Use ellipses only to indicate:

Pauses Longer Than 2 Seconds: Signifying a significant break in speech.
Dialogue Trailing Off: Showing that a speaker's thought is incomplete or fading.

Example:

I just don't know if...

4.2 Simplified Punctuation

Using Straightforward Punctuation for Clarity: Opt for simple punctuation marks to ensure clarity and ease of reading. Avoid complex structures that may complicate the subtitle.

Guidelines:

Avoid: Colons (:), semicolons (;), or other complex punctuation.
Prefer: Commas (,), periods (.), and straightforward sentence constructions.

Example: INCORRECT

He said: "I'll see you tomorrow."

CORRECT

He said, "I'll see you tomorrow."

4.3 Quotation Marks

Enclosing Dialogue: Use double quotation marks (" ") to enclose spoken dialogue. This practice clearly distinguishes speech from other text elements.

Example:

He said, "I'll see you tomorrow."

Quotes Within Quotes: Use single quotation marks (' ') for quotes within quotes to maintain clarity and proper formatting.

Example:

She said, "He told me, 'It's fine.'"

4.4 Numbers and Time

4.4.1 Numbers: Spell Out Numbers Zero to Ten: Use written words for numbers from zero to ten to maintain consistency and readability.

Example There are five apples on the table.

Use Numerals for Numbers Above Ten: For numbers exceeding ten, use numerals to ensure clarity and avoid clutter.

Example: She has 15 books.

Spell Out Numbers at the Beginning of Sentences: Always write out numbers when they start a sentence to adhere to grammatical standards.

Example: INCORRECT

15 people attended the meeting.

CORRECT

Fifteen people attended the meeting.

4.4.2 Time:

Use Numerals for Specific Times: Represent specific times using numerals for precision.

Example: The meeting starts at 9:30 a.m.

Formatting "a.m." and "p.m.": Use lowercase letters with periods and no spaces.

Example: 3:00 p.m.

5. Reading Speed and Accessibility

Maintaining an appropriate reading speed and ensuring accessibility are vital for accommodating diverse audiences, including those with varying reading abilities.

5.1 Recommended Reading Speeds

Maintain a Limit of 20 Characters Per Second (CPS): Subtitles should not exceed 20 characters per second, equating to approximately 160–180 words per minute (WPM). This limit ensures that subtitles are readable without causing viewers to rush through the text.

Implementation:

Calculate Total Characters: Divide the total number of characters (including spaces and punctuation) by the display duration in seconds.
Adjust Timing or Text: If the CPS exceeds 20, either shorten the text or extend the display time to maintain readability.

5.2 Increase Display Time for Specific Scenarios

Unfamiliar or Technical Terms: When subtitles contain specialized vocabulary or jargon, increase the display time to allow viewers to comprehend the terms fully.

Action: Extend the subtitle duration to accommodate the complexity of the terms.

Multiple Speakers in a Single Subtitle: Subtitles featuring dialogue from multiple speakers require additional time for each speaker's lines to be read comfortably.

Action: Ensure sufficient display time to read both lines without rushing.

Busy Visuals (e.g., Action Scenes): During scenes with intense visual activity, such as action sequences, viewers may find it harder to focus on reading subtitles. Increasing display time in these contexts aids in maintaining comprehension.

Action: Prolong the subtitle display to ensure readability amidst visual distractions.

Best Practices:

Adaptive Timing: Adjust subtitle timing based on context to enhance accessibility.
Consistency: Maintain consistent reading speeds across similar contexts to avoid viewer confusion.
User Testing: Conduct tests with diverse audiences to ensure that reading speeds are comfortable for all viewers.

6. Linguistic Accuracy

Linguistic accuracy ensures that subtitles faithfully represent the spoken dialogue, preserving the original intent and tone while maintaining readability.

6.1 Verbatim vs. Edited Subtitles

Verbatim Subtitles: Whenever possible, use verbatim subtitles to preserve the speaker’s exact words, tone, and intent. This approach maintains the authenticity of the dialogue and respects the original content.

Example:

"So, um, like, I don’t know, maybe we could, uh, try again?"

Edited Subtitles: Edit the content for readability only when the speech speed exceeds reading limits. This editing should aim to enhance clarity without altering the speaker's original message or tone.

Guidelines for Editing:

Maintain Meaning: Ensure that edits do not change the intended meaning of the dialogue.
Simplify Structure: Use simpler sentence constructions to facilitate easier reading.
Remove Filler Words: Eliminate unnecessary filler words (e.g., "um," "like," "you know") that do not contribute to the message.

Best Practices:

Balance Accuracy and Readability: Strive to maintain a balance between staying true to the original dialogue and ensuring that subtitles are easy to read.
Consistency: Apply editing rules consistently throughout the content to maintain a uniform viewing experience.
Respect Speaker's Voice: Avoid edits that could misrepresent the speaker's emotions or intentions.

7. Style and Consistency

Maintaining a consistent style and formatting across all subtitles ensures a professional and seamless viewing experience. Consistency aids in readability and helps viewers focus on the content rather than being distracted by stylistic variations.

7.1 Consistency Across Content

Uniform Formatting: Ensure that all subtitles within a project adhere to the same font style, size, color, and placement. Uniform formatting fosters a cohesive look and prevents distractions caused by abrupt changes.

Best Practices:

Font Selection: Choose a clear, legible font that remains readable across different screen sizes and resolutions.
Size and Color: Use a consistent font size and color that contrasts well with the background, enhancing visibility.
Placement: Maintain consistent subtitle placement (e.g., bottom center) unless specific visual elements necessitate changes.

Consistent Terminology and Style: Use the same terminology and stylistic choices throughout the subtitles. This consistency helps in maintaining the flow and avoids confusion.

Examples:

Terminology: Decide whether to use "TV" or "television" and stick with that choice.
Stylistic Choices: Whether to capitalize the first letter of each subtitle or use sentence case consistently.

Avoid Abrupt Changes: Refrain from making sudden changes in font, placement, or style within the same project. Abrupt variations can distract viewers and disrupt the viewing experience.

Example:

Incorrect: Subtitles switch from a white font at the bottom to a yellow font at the top without reason.
Correct: Subtitles maintain a white font at the bottom unless necessary to change for visual clarity.

Best Practices:

Style Guide: Develop and adhere to a subtitle style guide for all projects to ensure uniformity.
Review and Edit: Regularly review subtitles for consistency in formatting and style throughout the content.

8. Advanced Considerations

Advanced considerations in subtitle creation involve synchronizing subtitles with visual cues and managing scene transitions to enhance viewer comprehension and engagement.

8.1 Synchronization with Visual Cues

Aligning Subtitles with On-Screen Actions: Ensure that subtitles are synchronized not just with spoken dialogue but also with on-screen actions. This alignment enhances comprehension by providing context and reinforcing the connection between audio and visual elements.

Example 1:

[explosion sound]

We need to evacuate now!

The subtitle appears simultaneously with the visual explosion, enhancing the impact.

Example 2:

[door opens]

Who's there?

The subtitle coincides with the visual of the door opening, providing context.

Avoid Premature Display of Dramatic Subtitles: Do not display subtitles for dramatic events (e.g., explosions, sudden movements) before the visual occurrence. Premature subtitles can create confusion and disrupt the viewing experience.

Best Practices:

Timing: Carefully time subtitles to align with both audio cues and visual actions.
Contextual Relevance: Ensure that subtitles provide context without overshadowing the visual storytelling.

8.2 Scene Transitions

Managing Subtitles Across Scene Changes: When transitioning between scenes, do not carry subtitles into the new scene unless the dialogue explicitly continues across scenes. This practice maintains clarity and prevents confusion about the continuity of dialogue.

Guidelines:

End of Scene: Remove subtitles at the end of a scene unless the dialogue persists.
Continuing Dialogue: If dialogue continues into the next scene, ensure that the subtitle reflects the ongoing conversation without abrupt breaks.

Best Practices:

Clear Transitions: Ensure that subtitles do not overlap with scene transitions, maintaining visual and contextual clarity.
Consistent Style: Maintain the same subtitle style across scenes to preserve consistency.