Audio Stream Input/Output: A computer soundcard driver protocol for digital audio specified by Steinberg, providing a low-latency and high fidelity interface between a software application and a computer’s sound card. Whereas Microsoft’s DirectSound is commonly used as a stereo input and output for non-professional users, ASIO allows musicians and sound engineers to process their audio via Windows’ computer software instead of external hardware.

On a Windows Vista-based computer, an Audio Streaming Input and Output (ASIO) driver may not work correctly. When this problem occurs, you experience the following symptoms.

Symptom 1
When the ASIO driver calls the GetLinkPositionRegister routine that is provided in the Microsoft high-definition audio device driver interface (DDI), the GetLinkPositionRegister routine always returns 0 for the current direct memory access (DMA) position. In this situation, the ASIO driver may be unable to initialize. This symptom occurs only when certain hardware audio chipsets are installed. For example, this symptom occurs on a computer that has the ATI SB460 Southbridge chipset installed.

Symptom 2
An application can use the AUDCLNT_STREAMFLAGS_EVENTCALLBACK flag to open an exclusive-mode audio stream in pull mode. In this situation, the audio engine should signal an event that is provided by the application to indicate that the audio buffer is ready for processing. However, the audio engine does not correctly signal the event on a Windows Vista-based computer.