Closed Captioning

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A Closed Captioning Stream is a data stream hidden inside a video stream. It represents the audio portion as text.

An MPEG2 elementary video stream sometimes has closed captioning data embedded in it as EIA-608. In such cases the MPEG2 Decoder generates two output streams: Video and Closed Captioning.

Also, the AVI and OGG container formats can have closed captioning data as a separate stream. So if an MPEG2 file with closed captioning is converted to an AVI format, the resulting output file will have three streams: Video, Audio and Closed Captioning.

Functions that can be used to manage closed captioning include:

IltmmPlay::put_CloseCaptioning: Used to enable the display of closed captioning data.
IltmmConvert::put_AllowedStreams: Used to preserve Closed Captioning data during conversion from one format to another. The output format needs to be able to accept Closed Captioning data.
IltmmConvert::SetClosedCaptioningTargetFile: Used to save the decoded closed captioning data as either TEXT or SRT files.
IltmmCapture::put_CloseCaptioning:Used to enable the capture of closed captioning data.

Additional functions are listed in the See Also section.