The Wowza Video™ service can receive closed caption data from a video source so that captions appear when the stream is played. Closed captions make your streams accessible to hearing-impaired viewers and allow your streams to comply with the United States FCC 21st Century Communication and Video Accessibility Act (CVAA) of 2010.
About closed captions
Just as there are several protocols and formats for receiving and playing live adaptive bitrate streams, there are multiple types of closed-caption formats that can be used when streaming live events. Wowza Video can receive two closed-caption formats from a video source: CEA-608 (digital) and onTextData.
- CEA-608 supports playback over HLS on Apple iOS devices, VideoLAN VLC player, and many set-top boxes.
- onTextData supports playback over HDS and RTMP.
Some video sources can send either CEA-608 or onTextData captions to a transcoder. Other sources can send both. Whatever format or formats Wowza Video receives, it decodes and translates incoming caption events so that captions appear when the stream is viewed over all three playback protocols —HDS, HLS, and RTMP.
Notes:
- Wowza Video supports only the digital CEA-608 portion of the CEA-708 standard.
- If you are using Wowza Flowplayer, which is the player within Wowza Video, it only supports CEA-608 captions for playback in HLS streams.
- onTextData and CEA-608 captions are included in Wowza Video recordings, if you create them.
How closed captions work in Wowza Video
Closed captions in Wowza Video streaming are implemented through a process that involves embedding textual information into the video stream at the encoder. These captions are synchronized with the video content and displayed during playback.
Before you start
You need to have:
- A video source or an encoder
- Live caption provider
You should complete the following task:
- Create a live stream using any of the live stream intents.
Notes:
- If you create a live stream using the Custom Stream intent, you can select to include closed captions during the stream setup and don’t need to follow Steps 1-6 below.
- If you use 3Play media for live captioning, do not select CEA-608 (digital) or onTextData options during or after live stream creation. See Use live captioning with 3Play media and Wowza Video for information on how to set up live captioning instead of following the instructions below.
Follow these steps to include closed captions for a previously created live stream:
- Log in to Wowza Video.
- Go to Live streams in the navigation.
- Select a live stream.
- In the Live stream details page, click the Settings tab.
- Select the type of closed captions you need for your stream from the following:
- CEA-608 (digital) - Captions that can be played on devices and browsers that support HLS, including Wowza Flowplayer.
- onTextData - Captions that can be played on devices and browsers that support Adobe HDS or RTMP.
- Click Save Changes.
