Closed Captions

Closed captioning

Closed captioning is a great way to reach viewers who might not be otherwise able to consume your content. Whether because of a language barrier, hearing difficulty, or just people watching in a noisy location. There are a great many situations where captions or subtitles will improve the viewer experience.

ScaleEngine supports captions on both live and VOD content.

Live stream captions

We can receive captions in one of 2 formats: CEA 608/708 line captions, or AMF textData.

CEA captions are simple and easy. They're embedded in the video data, and will pass through our system seamlessly. Recorded files will contain the caption data and playback without any effort.

AMF captions require a bit more work, but offer multi-language support. You will need to contact us about setting up the caption ingest to handle the AMF events. We also support converting the recorded data track to subtitles usable for VOD.

VOD subtitles

We support 2 files types for VOD subtitles: WebVTT and TTML. For single bitrate VOD, simply place the subtitle file with the video file it belongs to, with the same name, except for the extension.

For example if you have a file called "sample.mp4", then place its subtitles in a file called "sample.vtt" or "sample.ttml".

WebVTT is much simpler and there are more utilties to convert it easily. It can also be easily edited by hand to correct transcription mistakes. We advise using WebVTT unless you have a specific reason not to.

TTML is a more advanced XML based markup format. Its main use is that is supports multiple languages in a single file.