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Subtitles, Closed Captions, and Open Captions: What's the Difference?

Captioning's Moment

I'm profoundly deaf. I rely heavily on my hearing aid, and every time I can watch something with captions, I will without a second thought.

Anecdotally, it feels like captions have been having a moment the past few years, as awareness of them — and the expectation of their presence — grows. In a few short years, we've gone from Rikki Poynter's No More CRAPtions campaign, a plea for YouTubers to invest in their videos' closed captions at all, to the more recent breathless reporting over the evocative captioning in Stranger Things and the news that more than half of Gen Z and millennial viewers prefer to watch TV with subtitles.

Meanwhile, Ubisoft found that in Assassin's Creed: Odyssey, which has captions on by default, 95% of players leave those captions on. This suggests, at minimum, that most of those players aren't finding the captions intolerable and outright rejecting their presence. At A11yTO Conf 2023, I heard from several folks in the game development industry who said that this very revelation has absolutely emboldened accessibility efforts in many game studios, leading to better, more usable defaults for games going forward.

One throughline I'm seeing in the reporting about captioning's current trendiness is that TikTok may have played a big part in normalizing the use of captions and subtitles for younger viewers. Again anecdotally, this would make sense to me. While I'm sure there's plenty of algorithmic self-selection bias at play here, it seems like many videos come across my For You Page where the creator has done the work to burn in their own subtitles, even alongside TikTok's own built-in closed captions feature. It's pretty commonplace to see those burnt-in subtitles prefixed with [CC] — short for closed captions. This is technically inaccurate in several ways, as we'll see pretty shortly, but I still think it's really useful shorthand nonetheless. Even if it's not technically right (and, honestly, saying anything in language is technically right is pretty fraught, given semantic drift), it absolutely signals the intent clearly enough.

In everyday language, terms like captions, closed captions, and subtitles all get used pretty interchangeably — and the [CC] abbreviation stands as shorthand for all of them. Within the professional transcription industry and amongst many deaf and hard-of-hearing consumers, however, these terms often have very particular meanings. Knowing the differences between them can help you pick, and better understand, the access tool that's right for your content and your viewers.

Broadly speaking, the differences here fall along two axes:

  • The difference between captions and subtitles is what I'd call the content axis.
  • The difference between open and closed captioning is the technology axis.

The Content Axis: Captions or Subtitles

While captions and subtitles are both transcriptions displayed synchronously with the audio, the difference between them is what content gets transcribed.

  • Subtitles are synchronized transcriptions of just the dialogue.
  • Captions are synchronized transcriptions of all meaningful audio — dialogue, laughter, applause, music, slammed doors, and more.

If a given video doesn't really have any non-dialogue audio, then the captions and the subtitles would be one and the same.

Subtitles generally assume a user can hear, and thus make out any laughter, applause, music, slammed doors, and so forth, but for whatever reason, need a hand in making out specifically what's being said. The most common use case for this is translation, although I also see subtitles crop up as a way to supplement poor audio. Because subtitles generally assume the user can hear, they might also omit elements that are more common in captions, such as speaker labels.

Captions, meanwhile, assume that the viewer can't hear as well, and thus seek to transcribe any audio that the viewer would find meaningful for understanding the video. They often follow conventions for helping the viewer better make sense of the transcription, such as labelling when different people start speaking, and they might use certain formatting standards to indicate when speakers are off-screen or when the speech is provided as a voiceover.

To see the difference, check out these two versions of the movie trailer for the film Creature with the Atom Brain:note 1

Trailer with (open) captions
Trailer with (open) subtitles

Here, both the captions and the subtitles are implemented as open captions, which we'll get to shortly. If the videos didn't load, or if you couldn't watch the videos for any reasons, feel free to check out the captions' text file and the subtitles' text file instead.

When it comes to the dialogue, the two versions are identical. Where they differ is that the captions include notes about the background music, gunshots, choking sounds, mysterious bubbling substances, miscellaneous explosions, and inaudibly mouthed words, whereas these cues would instead be considered superfluous in the subtitles.

The Technology Axis: Open or Closed Captioning

If you've ever wondered what makes closed captioning closed, or if there's also an open captioning, then the technology axis is for you. The difference between open captioning and closed captioning comes down to how the synchronized transcription is provided/associated with the video:

  • Open captioning is when the synchronized transcription is burned into the video — i.e., added to the actual pixels of the video using some video-editing software.
  • Closed captioning is when the synchronized transcription is supplied as metadata for the video or sent as an additional file, which allows the captions to be turned on and off.

We can see the difference by revisiting our favorite creatures with atom rays of superhuman strength. In the second demo, you should be able to go into your video player's controls and turn the captions on and off.

Trailer with open captions
Trailer with closed captions

Between the two, closed captioning generally affords the viewer much more flexibility:

  • Toggling them on/off: Any viewer can opt into captions if they find them helpful, or opt out of them if they find them distracting.
  • Controlling their visual presentation: Depending on the video player, viewers may be able to select the fonts, colors, backgrounds, sizes, and placements that work best for their needs (whereas with open captioning, you might get stuck with captions that are incredibly small, tucked out of the way, placed against busy backgrounds, or which have horrendous color contrast — I've seen tiny captions in white text on a soft pink background on TikTok before, for instance)
  • Switching languages: Multiple tracks for different languages' subtitles can be provided via closed captioning technologies, letting users opt into the language they want.

Additionally, closed captions won't fall victim to overzealous video compression, and video players can nudge the captions around to accommodate things like hiding and revealing other controls, ensuring the captions don't get covered up. From a creator standpoint, closed captions are also generally easier to update after the fact, since updating them usually doesn't require editing and reuploading a whole new video.

Open captions, edited into the pixels of the video itself, have their benefits, too, however:

  • Necessary for platforms which don't support closed captioning: Open captioning works anywhere that videos do, whereas not all platforms support uploading closed captions.
  • Reshareability/portability: When viewers save videos, closed captions aren't always guaranteed to save as well. If there's a chance that the saved video gets reuploaded somewhere else, it would then be missing its captions — whereas open captions are guaranteed to remain part of the video, save for some serious editing out.
  • Fault tolerance: If a platform supports closed captions but the support is particularly unreliable (such as during TikTok's rollout of closed captions, where users' ability to see or add captions regularly broke) or where added captions are somehow prone to disappearing, then it's probably best to treat the platform like you would a platform that doesn't support closed captioning in the first place.
  • No tech know-how required to use: Since open captions don't need to be turned on, viewers don't have to navigate their video player or app to take advantage of them. This is especially helpful when your target audience is less comfortable with technology, or when your video player is more of a one-time experience rather than a regularly returned-to app.
  • Mitigating poor audio quality: In some cases with poor audio quality where everyone would struggle to make out what's being said, including many people who wouldn't necessarily already have captions turned on, open subtitles can momentarily pop in to clarify the dialogue for everyone.

Closed and open captioning look a little different in the world of movie theaters. Deaf and hard-of-hearing patrons can request closed-captioning peripheral devices, such as glasses or readouts you stick in your cupholder. In practice, patrons often find these devices unreliable, poorly synchronized, connected to the wrong film, uncharged, or difficult to arrange in their field of view. Meanwhile, while such showings are rare, open-captioned showings of films project the captions along with the rest of the movie for everyone in the theater to see without needing any extra devices.

Learning More

Ideally, don't use this article as an excuse to start reaching out people who have prefixed their open subtitles with [CC] or anything like that. I don't think that's particularly helpful.

Instead, my hope for this article is to spark more curiosity and understanding for the world of captions, subtitles, and other transcription, as well as for the needs of deaf and hard-of-hearing viewers. If you're creating videos, please transcribe them! Even in the midst of the generative AI hype cycle, manually curated transcriptions are still the best, most accurate experience, and they are invaluable for folks who need them.

If you'd like to learn more about making the best captions and subtitles for your viewers, here are some of my favorite resources:


Footnotes

  1. This trailer was not released with a copyright notice, as was required of the time, and is therefore in the public domain. Retrieved on Wikimedia Commons. |