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Custom Audio Effects in Windows Vista Custom Audio Effects in Windows Vista
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| bet | 7/28 | | Sana | 22.07.2021 | | Hajmi | 0.57 Mb. | | #15720 |
Figure 1 shows how the sAPOs for a logical device are incorporated into the Windows Vista audio architecture. The audio engine runs in user mode and supports a signal processing graph that processes the audio stream. An sAPOs is essentially a plug-in to the signal processing graph. Some notes on the figure include:
There is one LFX sAPO for each logical device, but each application that is streaming to the audio engine has its own instance of that sAPO.
The GFX sAPO is inserted in the engine’s device graph. Each logical device has only a single instance of the audio engine and GFX sAPO. The GFX sAPO passes the audio stream to the PortCls audio adapter and ultimately to the output device.
An sAPO runs as LocalService and cannot access any resources that do not have the appropriate access control list (ACL) setting.
An sAPO runs with limited privileges. The exact set depends on which services are running in the audio service's svchost instance. However, sAPOs should not be performing any operations that require privileges.
An sAPO should not access the network.
Figure 1. Basic Windows Vista audio architecture
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