 Starting with Windows Me, the waveOut, DirectSound, and DirectShow APIs support non-PCM formats such as AC-3 or WMA over S/PDIF and non-PCM data goes directly to the class driver instead of going through KMixer.A new kernel-mode API, "Direct Kernel Streaming", was also introduced in Windows 98 in order to bypass the KMixer and avoid problems associated with it.KMixer doesn't alter the sound in the majority of cases.