What is Closed Captioning? CC Explained

Closed Captioning


Closed captioning (CC) is often a misunderstood aspect of the post-production process. Below are common questions about closed captioning that we often hear at Line 21:

1. What’s the difference between closed captioning and subtitling?

While both CC and subtitling display text on screen, closed captioning is meant for a non-hearing audience and so includes non-verbal information in addition to what speakers say. This can include sounds effects, speaker IDs, and positioning (left, right, centre) to indicate who is speaking.

Subtitling assumes that the audience can hear but doesn’t understand the language, so it deals with what the speakers say but doesn’t include the non-verbal information.


Hint: If you are planning to do both captioning and subtitling for your project, let your closed captioning provider know. It is more efficient to build captioning and subtitling at the same time. A good practice is to build a timed master English subtitling list to form the basis of all future language versions.

2. What’s the difference between open and closed captioning?

Open captions are visible to all viewers, whereas closed captions are only visible to those who activate them.

3. When do I need closed captioning?

You need closed captioning any time you want to include viewers who can’t fully hear or appreciate your audio for reasons that might include hearing loss, a noisy surrounding environment, or because they are learning the language.


Broadcasters are required by law to include captioning, but it is also a great way to give viewers another way to receive information. For instance, have you ever watched a film where the accents were so strong, or the voices were so quiet, that you weren’t entirely sure what was said? Good captioning would help you out here.


Captioning transcripts can also be used as the basis for fantastic dialogue lists and other post-production scripts. If you are planning a web presence, consider posting the transcript (or portions of it) to your blog or website.

4. Are there different types of closed captioning?



You probably see online captioning fairly often when watching sports and news or current events programming that goes straight to air. Online captioning is also known as realtime captioning, and is performed by stenographers. You should expect excellence in realtime captioning, but also realize that the captioner can’t stop to look up any unfamiliar terms, and that they don’t have the opportunity to go back over their work. Realtime captioning is done as rollup-style captioning.


Line 21 does offline captioning, where we work on captions in advance of broadcast. This gives us the opportunity to give your captioning an extra several passes. There are two main kinds of offline captioning:


Roll-up captioning: is used when time is tight to broadcast, and when there are few changes of speaker. The captions are not phrased for clarity, and normally the viewer has to figure out from the picture who is talking. Rollups are the least labour intensive method of captioning, and should therefore be the least expensive…but the transcript should still be perfect.


Here’s an example of roll-up captioning:



Pop-on captioning: more closely resembles subtitling, where the captions are phrased into 2-line titles which display sequentially, each one individually timed. Each caption should form a unit of meaning, and should be phrased to make it easy to read and understand.


Here’s an example of pop-on captioning:


5. How can the closed captioning process be made easier?

Know what all of your deliverables are and in what formats (as much as possible), before you start captioning, post production scripting, or subtitling.


Let your service provider help you plan the best process for your project. For instance, sometimes you will not be able to provider a copy of your show with final audio and picture, but your captioners will be able to start with preliminary media and finish to final media or final notes to shorten your final delivery timeline.


Also, always make sure to tell your captioners about any changes made to audio or picture after they have started work, or your captioning won’t match your final picture.

Find out more information about Line 21’s captioning services.


October’s Recipe: Broiled Vegetables with Yogurt

This might sound crazy, but… trust us.

  • 2c yogurt
  • 1t thyme
  • 2 tomatoes
  • 1 or 2 onions
  • some heavy-bodied vegetables: maybe 3-4 potatoes, 2 eggplants, or a head of cauliflower
  • some medium-bodied vegetables: zucchini, mushrooms, peppers, enough to cover the  bottom of a roasting pan when chunked
  • 3/4 c olive oil
  • lemon wedges
  • salt and pepper

Coat the bottom of a roasting pan with 1/4 cup olive oil.

Slice your heaviest vegetables into 1/2 inch slices or use cauliflower florets to make a single layer in the bottom of the roasting pan. Sprinkle with salt, and broil until brown and tender, flipping once. Remove from pan and put in mixing bowl.

Re-oil the pan and blacken the medium-bodied vegetables and onions, roughly chopped, under the broiler. Remove from pan and put in bowl.

Re-oil pan and put in the tomatoes, halved, cut side down. Broil until the skins blacken, remove the tomatoes, and chop. Add to bowl.

Toss all vegetables in the bowl with the yogurt and thyme. Salt and pepper to taste, put the mixture in the roasting pan, and broil until charred on top. Serve with lemon. Amazing!

Thanks to Mark Bittman.