ViewCast Osprey-450e - Manual (Page 65)

Osprey 240e/450e User Guide
ViewCast 59
AVStream driver reference information
DirectShow technology uses terms with specific meanings. For example, filter, pin, driver and device
appear frequently when discussing DirectShow media standards. Figure 53 depicts the relationship
of DirectShow terms as they apply to Osprey hardware and drivers.
Figure 53. DirectShow
At the bottom of this diagram are one or more physical Osprey hardware devices. All Osprey devices
of a given type (such as Osprey 230 or Osprey 560) are controlled by a single Osprey binary, the
Osprey AVStream driver. For each physical device the AVStream driver creates one logical Video
Device and one logical Audio Device.
On top of each Osprey logical Video Device, one or more Video Filters is created. If the SimulStream
option is not installed, there is a single Video Filter for each Video Device. If SimulStream is installed,
there can be multiple Video Filters for each Video Device.
The distinction between Device and Filter is important mainly to SimulStream users. For non-
SimulStream users, Device and Filter effectively mean about the same thing. For SimulStream users,
each SimulStream Filter acts as a virtual device that can be accessed by name and can deliver a
separate video stream with its own independent control settings.
When SimulStream is enabled, some functions and capabilities are device-level, and others are
filter-level. Examples of device-level functions are input select, and the controls for brightness,
contrast, hue, saturation, and sharpness. These are closely tied to the underlying hardware of the
device, which inherently allows only one input to be selected at a time, and one set of hardware
control settings to be applied. Examples of filter-level functions are crop, logo, and caption settings,
which can be different for each video filter, and in fact for each pin of each filter. Some other
capabilities such as deinterlace and software gamma correction could logically be either device-level
or filter-level, but are treated as device-level for practical reasons.