ViewCast Osprey PCI, Руководство пользователя

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Osprey PCI User Guide
ViewCast 89
Audio properties
Many applications, including Windows Media Encoder, display a property dialog for setting audio
source and volume level. This page is a general-purpose DirectShow property page that our driver
has to support, but which is not quite intuitive in its operation.
To select the audio source:
1. Select the desired input in the Pin Line: selection box.
2. Click Enable .
Note: This action will deselect whichever input had been previously selected.
The confusing part comes up when you select any input other than the first on the list, which
happens to be Unbalanced. Let’s say you click
Master Volume . When you close and reopen the
dialog it displays Unbalanced in the selection box. It will look like the selection has been lost, but
then you will notice that
Enable is not checked. If you again click Master Volume , the Enable box
will automatically show up as checked.
With the Osprey 530/540/560, which has multiple audio inputs, further confusion arises if you
forget which input you had selected in the previous session and for some reason you want to
discover this rather than just select an input for the new session. The only way to do that is to try all
the inputs listed in the select box until you find the one for which Enable is checked.
This property page makes more sense if you understand that it is designed to allow mixing of audio
inputs for devices that support that. Osprey audio capture filters do not support mixing of inputs -
you have to select one stereo input at time - so the DirectShow design is not very convenient in our
case.