DCMP Closed Captioning Standards

November 6, 2015 BY EMILY GRIFFIN
Updated: June 3, 2019

The Described and Captioned Media Program (DCMP) provides services to support the academic success of students with sensory disabilities. 3Play Media invited Jason Stark, a Project Director at the DCMP, to present the DCMP’s closed captioning standards (“Captioning Key”) in the webinar, Understanding Closed Captioning Standards and Guidelines.

While the DCMP’s Captioning Key differs somewhat from 3Play Media’s closed captioning standards, it is a helpful resource for some captioning vendors and for institutions that do their own captioning in-house.

Watch a recording of the webinar below, or read on for highlights.


What Are Closed Captions?

Closed captions are time-synchronized video text that captures both speech and other relevant sounds, with the assumption that the viewer does not have audio.

Captions relay not only what is said but also what is being communicated.

Captions relay not only what is said but also what is being communicated. In other words, captions are more than a straightforward transcription of the spoken words.

Why Caption Quality Matters

When captions are not high quality — meaning they are not correctly synchronized with the audio, not properly formatted, or contain grammatical or spelling errors — an individual who is deaf or hard of hearing will not have full access to the video’s content.

An example of poor quality captioning:

Screenshot of video with caption: 'brilliant student, the best sign tifk observer he had ever known.'

To ensure that video captions are fully accessible to all viewers, the DCMP sets standards for closed caption quality in the form of the Captioning Key. These standards are not legal requirements, but rather guidelines to aim for.

Captioning Key’s 5 Measures of Quality

  1. Accuracy — Errorless captions are the goal. Correct grammar and punctuation are important to convey intended meaning (e.g., “Let’s eat, Grandma” vs. “Let’s eat Grandma”).
  2. Consistency — Uniformity in style and presentation of all captioning features is crucial for viewer understanding.
  3. Clarity — A complete textual representation of the audio, including speaker identification and non-speech information, provides clarity.
  4. Readability — Captions need to be displayed for long enough to be read completely. They need to be synchronized with the audio, and they must neither obscure nor be obscured by the visual content.
  5. Equality — Equal access requires that the meaning and the intention of the material are preserved as much as possible.

Captioning Key’s Closed Caption Formatting Guidelines

Captioning Key offers guidelines for how to format and display captions for maximum readability.

Recommendations include:

  • Limit lines to 32 characters or less, including spaces.
  • No more than 1-2 lines of text per screen.
  • Screenshot of video with caption correct vs. incorrect character length and number of lines

  • Use sentence case instead of ALL CAPS.
  • Screenshot of video with caption correct vs. incorrect capital letters

  • Use font that has ascenders and descenders, i.e., where letters like y, g, p, and q extend below the baseline, and letters like t, h, l, b, d, and f extend above the topline of other letters.
  • Use an average font weight, not too thin or too heavy.
  • Screenshot of video with caption correct vs. incorrect font weight

  • Text should be centered on the screen and left-aligned.
  • Screenshot of video with caption correct vs. incorrect alignment

Captioning Key’s Open Caption Formatting Guidelines

Certain formatting options are only possible with open captions, which are burned into the video file. Compare this with closed captions, which can be toggled on and off by the viewer and whose formatting can be adjusted in the video player.

If you’re producing open captions, the DCMP recommends:

  • White text on a gray, translucent background.

Grammar and Line Breaks

When creating a line break in a caption frame, the Captioning Key recommends these practices to preserve correct grammar and clarity:


Do not separate a modifier from the word it modifies.

Correct Incorrect
Mark pushed
his black truck
Mark pushed his black

Prepositional Phrases

Don’t break up a prepositional phrase.

Correct Incorrect
Mary scampered
under the table.
Mary scampered under
the table.

Name or Title

Don’t break up a person’s full name or title.

Correct Incorrect
Bob and Susan Smythe
are at the movies.
Bob and Susan
Smythe are at the movies.
Suzy and Professor Barker
are here.
Suzy and Professor
Barker are here.


Don’t add a line break immediately following a conjunction.

Correct Incorrect
In seconds she arrived,
and he ordered a drink.
In seconds she arrived, and
he ordered a drink.

Verb Phrases

Don’t separate an auxiliary verb from the word it modifies.

Correct Incorrect
Mom said I could have gone
to the movies.
Mom said I could
have gone to the movies.


Never end a sentence and begin a new sentence on the same line – unless they are very short, related, 1-2 word sentences.

Correct Incorrect
He suspected that his face
turned pale.
He suspected that his face
turned pale. He knew he

Screenshot of a rodeo with sound effect captioned:

Sound Effects and Music

Captions must accurately convey any sounds that are important to create an equal viewing experience without audio. DCMP recommends these practices for captioning sound effects:

  • The source of the sound effect should be included within brackets, unless the source of the sound is clearly seen on screen.
  • Sound can either be described or spelled out with onomatopoeia – or both.
  • Sound effect captions should be in all lowercase letters.
  • Offscreen sound effects should be italicized.
  • Be as objective as possible in describing music in captions.
  • If music has lyrics, caption the lyrics verbatim.
  • When a song begins, lyrics should be introduced with the name of the vocalist or artist and the song title in brackets.
  • Screenshot of a video with caption:

  • Add musical note icons at the start and end of lyrics.

Speaker Identification

To maintain clarity, captions must establish the identity of who is speaking, both onscreen and offscreen. If someone is speaking from offscreen, you should use italics and [offscreen] to indicate this.

When someone starts speaking, their caption should begin with their name as a speaker ID. If their name is unknown, you can use another label such as “DOCTOR”, “WOMAN 1”, or “NARRATOR”.

Speaker IDs can be in all caps or in parentheses, but whichever you choose, be consistent.


Captions should preserve the speaker’s tone of voice when it is relevant for communication.

For example, if a character’s emotion is not evident visually on screen (maybe they are offscreen, or their face is obscured), but their voice shows that they are angry, include [angrily] in their caption. Same with tags like [whispering] or [shouting].

Note: when people are pictured speaking but there is no audio, make sure to include a [no audio] or [silence] caption so the viewer knows they aren’t missing anything.

For more details on the DCMP’s Captioning Key, check out:

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