ViewCast Osprey PCI, User Manual

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Appendix B: Digital Video on the Osprey 300
104 ViewCast
Graphs
This section contains more technical information that may give some users helpful insight into DV
capture and rendering operations. The illustrations are DirectShow graphs as displayed by
GraphEdit.
For still more advanced information, refer to the DirectX 9 SDK documentation available from
Microsoft.
This graph shows the simplest possible video-only DV capture graph.
Figure 72. Video-only DV capture graph
This is the simplest possible audio + video DV capture graph. The difference is that the DV Capture
Filter’s A/V Out pin is used, which delivers an interleaved A/V stream rather than a pure video
stream. The AVI file will be “Type 1” - that is, the audio + video will be structured as a single stream;
this format is efficient but is DirectShow-only, not backwards-compatible to Video for Windows.
Figure 73. Audio + video DV capture graph
This is the simplest possible audio + video “Type 2” graph. The AVI file, now Video for Windows
compatible, is now structured as an “auds” stream plus a “vids” stream. The DV Splitter Filter splits
the interleaved A/V stream in to a dvsd video stream plus a PCM audio stream.
Figure 74. Audio + video Type 2 graph