Closed Captions and Teletext

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Analog television signals can carry extra information in the vertical blanking interval (VBI), including closed captions and World Standard Teletext (WST). DirectShow provides a set of filters for decoding and viewing both CC and WST text.

Analog Television