There are two different types of captioning:

Closed captions give viewers the option of switching the captions on or off while watching a video. They are the most common form of captioning and can be identified by the [CC] symbol. Closed captions can only be displayed when the media player or video sharing site (e.g. YouTube or Vimeo) supports it.
Open captions, also known as burned-in, baked on or hard-coded captions, are seen by everyone who watches the video. Open captions are a permanent feature on the video and can’t be turned on and off. Open captions are often used for videos which are being played on website video players that don’t have closed captioning functionality.

Which is better?

If YouTube is used to upload videos into your course, providing closed captioning is the easiest option. YouTube allows you to easily edit auto-generated captions, create your own, and upload your transcript.

Inclusive learning environment benefiting all learners. Automatically turn-on closed captioning when a video is played by managing YouTube's default setting.

Closed Captions

Advantages

Closed captions can be turned on and off by students.
Closed captions can easily be edited and have changes made to them (if you are the author or have access to edit the captions.)
Closed captions come in a range of file formats, making them suitable for a variety of media players.

Limitations

Closed captions place responsibility on the viewer to understand how to turn the captions on and off. (However, in YouTube, if you created the video, there is a setting in YouTube to automatically turn on closed captioning upon playing the video.)
The captions will only work if the media player supports closed caption files.

Open Captions

Advantages

Open captioning has universal design benefits for people other than those with hearing impairments, for example:
- people whose first language is not English
- people in noisy airports, health clubs, sports bars, etc.
- when the spoken word of all speakers is open-captioned, additional translation for speakers who have speech impairments is not required.
Open captions are easy to use because they do not require special functionality for media players to be able to display the captions.
As the open captions are permanently burned into the video, you don't have to worry about keeping track of a separate video file and caption file.

Limitations

Open captions are embedded directly into the video stream of a video, making it impossible to disable them for viewers who don't want them.
The quality of open captions is also tied to the quality of the video. If a video is blurry or low-quality, the captions can also be blurry and may be difficult to read.