ViewCast Osprey-450e - Manual (Page 51)

Osprey 240e/450e User Guide
ViewCast 45
Render NTSC Closed Captions On Video
Figure 38. Render NTSC Closed Caption On Video
The 4.5 driver can internally render closed captions on video when NTSC video is selected on the
input (Figure 38). There is a control to select which channel to render (although CC 1 is the only
channel that is commonly used).
This control only affects rendering on video performed internally by the driver. The AVStream 4.5
driver has two additional ways of delivering captions.

First, it exposes a DirectShow-standard CC pin. This pin can be used directly by applications
such as Windows Media Encoder’s scripting facility.

Second, the driver has a proprietary Closed Caption API for use by C++ developers. It
delivers raw captioning data from any CC or Text channel. It also delivers line-interpreted
data from these channels, suitable for a scripting display or for capture to an ASCII file. Is
also delivers XDS – “Vchip” and other ancillary data – in raw form.
Render Logical White As
The control group Render Logical White As (Figure 39) maps white captions to a color other than
white. This feature is a proprietary extension to the Closed Captioning standard. When logical white
is mapped to, for example, red, the CC standard captioning red also works; however, it is not
possible to distinguish “logical white” red captions from “standard colored” red captions. Since
standard colored captions are so little used, this characteristic has little practical effect.
Figure 39. Render Logical White As