NABTS/FEC VBI Codec Filter

The NABTS/FEC VBI codec is a kernel-mode stream class filter used in analog television filter graphs. It processes captured VBI lines and distributes decoded and/or forward-error-corrected SLIP packets containing NABTS data downstream to the BDA SLIP Deframer, the BDA IP Sink and ultimately to Winsock. There are no application-callable interfaces on this filter.

The NABTS/FEC VBI codec has two input pins, VBI and HWNABTS. The VBI pin is used if the capture filter is delivering raw VBI data, and the HWNABTS pin is used if the capture filter is delivering decoded VBI data; in this case, the NABTS/FEC VBI codec simply passes the data through to the BDA SLIP Deframer.

The NABTS/FEC VBI codec appears in GraphEdit under the "WDM Streaming VBI Codecs" category. Because this is a kernel-mode filter, applications cannot co-create it directly, but must use the System Device Enumerator to instantiate it, as described in Enumerating Devices and Filters. This filter must be added to the graph manually using the IFilterGraph::AddFilter method; the Capture Graph Builder cannot be used to add this filter to the graph.