The Difference Between CEA-608 and CEA-708 Captions

Posted by Anne Quach on October 14, 2021.

Captions on television must follow the standards of the Federal Communications Commission. Two standards of closed captioning are currently used for broadcast television – CEA-608 and CEA-708 Captions. In the absence of captions, your videos might not be broadcasted as it is against the regulations of many countries. More importantly, having closed captions in your videos aired on television means a larger audience, especially those who cannot hear the sound well and social media users can get access to your content.

In today’s post, we will go into the features and differences between CEA-608 and CEA-708 captions and help you find out which type of captions you should use for your broadcast content.

CEA-608 Captions

CEA-608 captions (also known as Line 21 captions) were the standard for closed captions for analogue broadcast television in some American countries including the US, Canada, and Mexico. Nowadays, CEA-608 captions have mostly been replaced by CEA-708 captions for digital television. However, they can still work with some specific digital broadcasts.

608 captions are usually displayed in the form of black-box background and all-uppercase white text. Their fixed position is at the bottom of the screen.

CEA-608 captions
Source Image: Giovanni Galvez

Line 21 captions have two fields which only allow two language captions to be displayed. The list of supported languages for this type of caption is limited to 7 languages including English, Spanish, French, Portuguese, Italian, German, and Dutch due to its lack of special characters. For example, the English captions are usually transmitted in the first field and Spanish captions are in the second field.


CEA-708 Captions

CEA-708 captions are the more modern caption format designed for digital broadcasts in North America and follow more advanced standards from FCC. For example, FCC’s latest quality standards require that captions should not overlap one another or block other important visual content on the screen. While the position of 608 captions is fixed which might violate the FCC’s rule, 708 captions may appear anywhere on the screen to comply with this standard.

With 708 captions, viewers are able to select different caption appearances with 8 fonts, 3 text sizes, 64 text colours and background colours. Background opacity and drop shadowed/edged text are also allowed.

CEA-708 captions work with nearly every language. In addition, they include speaker identification, punctuation, and non-speech noises.


What is the difference between CEA-608 captions and CEA-708 captions?

CEA-608 Captions CEA-708 Captions
Standard The standard for analogue television The standard for digital television
Transmission Encoded in Line 21 of the TV signal Embedded in MPEG-2 streams
Compatibility Can be transmitted on analogue & digital television Can only be transmitted on digital television
Text appearance The text size and font are fixed.

The text colour is white and the background is black.

3 text sizes and 8 font sizes are supported.

64 text colours and 64 background colours with various background opacity and drop shadowed text.

Caption position Fixed Can be repositioned if they overlap important visual information.
Languages supported  7 languages: French, German, Italian, Dutch, English, Portuguese, or Spanish Any language
Number of captions Only 2 languages at a time Multilingual captions


The Future of 608 vs. 708 Closed Captions

Although CEA-608 captions can work with analogue and some other digital broadcasts, they generally do not comply with many FCC requirements on closed captioning standards. For instance, they do not support background colours other than black and the caption position is fixed at the bottom of the screen which may block other important visuals. Thus, CEA-608 captions are considered an outdated format for broadcasts.

708 closed captioning, on the other hand, allows content on digital television to easily transition to web content with full accessibility. In addition, 708 captions are supported on both Android and iOS devices.


What file format should you use for CEA-708 captions?

The standard caption file format for CEA-608 and CEA-708 captions are Scenarist (.scc). This format is recommended by Youtube and is also compatible with many video distribution platforms such as Vimeo, Amazon, iTunes, and Netflix.


Get your Scenarist (.scc) caption file with GTE Media

GTE Media’s team supports a wide range of output formats for your closed captions, including the Scenarist (.scc) format that works well with both digital television and online distribution platforms. Have a 1:1 consultancy with our media localization expert today to learn more about our closed captioning services and how they can help you grow in global markets.



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