The IDirectSoundCaptureBuffer::Start method puts the capture buffer into the capture state and begins capturing data into the buffer. If the capture buffer is already in the capture state then the method has no effect.
HRESULT IDirectSoundCaptureBuffer::Start(
DWORD dwFlags
);
DSCBSTART_LOOPING
If the method succeeds, the return value is DS_OK.
If the method fails, the return value may be one of the following error values: