CC Decoder Filter

The CC VBI Decoder is a kernel-mode stream class filter. It appears in GraphEdit under the "WDM Streaming VBI Codecs" category. It accepts sample waveforms delivered by a capture filter and delivers decoded closed-captioning data to the Line 21 Decoder and/or to interested applications.

This filter has two input pins, VBI and HWCC. The VBI pin is used for raw VBI data, and the HWCC pin is used when the VBI decoding is performed in hardware by the capture filter. When the data is received on the HWCC pin, the CC Decoder operates in "pass-through" mode, and sends the data directly to the Line 21 Decoder without processing it in any way. If the capture filter exposes an HWCC pin, it must be connected directly to the corresponding pin on the CC Decoder. The pin category is PINNAME_VIDEO_CC_CAPTURE.

The CC Decoder has up to eight output pins, each of which can select their own lines and substreams. The first output pin is connected to the Line-21 Decoder.

The CC Decoder filter appears in the "WDM Streaming VBI Codecs" filter category (AM_KSCATEGORY_VBICODEC).

Because this is a kernel-mode filter, applications cannot create it directly using CoCreateInstance. Instead, use the System Device Enumerator. For more information, see Creating Kernel-Mode Filters.

See Also

• Viewing Closed Captions