Cooperative Levels

[The feature associated with this page, DirectSound, is a legacy feature. It has been superseded by WASAPI and Audio Graphs. Media Casting have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Media Casting instead of DirectSound, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Because Windows is a multitasking environment, more than one application can be working with a device driver at any one time. Through the use of cooperative levels, DirectX makes sure that each application does not gain access to the device in the wrong way or at the wrong time. Each DirectSound application has a cooperative level that determines the extent to which it is allowed to access the device.

After creating a device object, you must set the cooperative level for the device by using the IDirectSound8::SetCooperativeLevel method. Unless you do this, no sounds will be heard.

The following example sets the cooperative level for the DirectSound device represented by the IDirectSound8 interface at lpDirectSound. The hwnd parameter is the handle to the application window.

HRESULT hr = lpDirectSound->SetCooperativeLevel(hwnd, DSSCL_PRIORITY);
if (FAILED(hr))
{
  ErrorHandler(hr);  // Add error-handling here.
}

DirectSound defines three cooperative levels for sound devices, specified by the values DSSCL_NORMAL, DSSCL_PRIORITY, and DSSCL_WRITEPRIMARY. These levels are explained in the following topics:

• Normal Cooperative Level

• Priority Cooperative Level

• Write-primary Cooperative Level