Gutspiller
07-15-2004, 06:37 PM
Let's start with the origins of the High Definition Audio specification. With the oblivion of DOS and the arrival of Windows the era of motley architectures and direct sound card programming came to an end. OS Windows resulted in the appearance of unified standards and APIs. In this case API (Application Programming Interface) is a unified standard interface, which is used for high-level access to similar functions of various devices, instead of low-level programming of each device. As applied to audio, OS Windows 3.11 contained MME (Multi Media Extensions) as part of Windows API with several simplest functions for initializing devices, setting up working parameters, replaying and recording audio. In 1996 Microsoft released a rather powerful DirectSound API with multi-channel audio support, software emulation, and capability for hardware acceleration of audio functions, so all sound cards commenced acquiring DirectSound drivers.
In 1997 Intel introduced a standard specification on cheap audio-codecs for the masses, named AC‘97 (Audio Codec '97). The main achievement of the introduction of this specification was the audio quality improvement in popular sound cards due to complete separation of analog and digital sections, and the raise in maximum playback sample frequency up to 48 kHz for compatibility with the audio format in DVD-Video. The standard endured rather long, lived to see v2.3, and is presently obsolete.
Digit-Life.com (http://www.digit-life.com/articles2/intel-hdaudio/intel-hdaudio.html)
In 1997 Intel introduced a standard specification on cheap audio-codecs for the masses, named AC‘97 (Audio Codec '97). The main achievement of the introduction of this specification was the audio quality improvement in popular sound cards due to complete separation of analog and digital sections, and the raise in maximum playback sample frequency up to 48 kHz for compatibility with the audio format in DVD-Video. The standard endured rather long, lived to see v2.3, and is presently obsolete.
Digit-Life.com (http://www.digit-life.com/articles2/intel-hdaudio/intel-hdaudio.html)