ViewCast OSPREY 240E, Руководство пользователя

Страница: 90 / 106

The Audio Driver
84 ViewCast
Audio formats
The Osprey hardware supports sampling of analog audio at 32, 44.1 and 48 kHz in 16-bit PCM format.
Captured audio data is down-sampled and reformatted if necessary by Microsoft system audio
components, allowing an application to capture audio data in 8-bit and 16-bit mono or stereo formats at
any of the following data rates:

8 kHz

11.025 kHz

16 kHz

22.05 kHz

32 kHz

44.1 kHz

48 kHz
Audio playback
Osprey cards provide audio capture only, not audio playback. Continue to play back captured audio
using your system soundcard.
Audio configuration
The OspreyConfig applet is included as part of the Osprey AVStream driver package. It is also provided in
source form in the Osprey AVStream SDK. It provides supplementary controls that are not available via
the standard system properties.
OspreyConfig’s controls are device-specific and apply only to Osprey audio capture devices. Use the
Device menu list at the top of the applet’s window to select which device you are controlling.
Mono Source Mode
If set to Use Left Channel , then left channel audio data is copied to the right channel.
If set to Use Right Channel , then right channel audio data is copied to the left channel.
If set to Average Left and Right , no copying is done.
The Microsoft mixer component always averages both channels when converting to mono. If a signal is
present on, say, the left channel only, the Average mode will average the left channel with the silent
right channel, effectively halving the signal amplitude. Setting this control to Left results in only left
channel data in the mono capture, with no amplitude drop.
Dual Mono
The Dual Mono window enables a special mode of the driver in which the left and right stereo pair
inputs to a device are used as two separate mono channels serving two separate audio capture filters. A
typical use for this mode is audio-only applications where stereo is not needed and maximum density of
inputs per system is the driving factor.