DirectSound
From Wikipedia, the free encyclopedia
DirectSound is a software component of the DirectX library, supplied by Microsoft, that resides on a computer with the Windows operating system. It provides the interface between applications and the sound card, enabling applications to produce sounds and music. Besides providing the essential service of passing audio data to the sound card, it provides many needed capabilities. Of these audio mixing and volume control are the most essential.
DirectSound also allows several applications to conveniently share access to the sound card at the same time. Its ability to play sound in 3D added a new dimension to games. It also provides the ability for games to modify a musical script in response to game events in real time, ie: the beat of the music could quicken as the action heats up. DirectSound also provides effects such as echo, reverb, and flange.
After many years of development, today DirectSound is a very mature API, and supplies many other useful capabilities, such as the ability to play multichannel sound and sounds at high resolution.
In DirectX 8, DirectSound, DirectSound3D became part of DirectX Audio.
[edit] DirectSound3D
DirectSound3D is an addition to Microsoft's DirectX system which is intended to standardize 3D audio under Microsoft Windows, introduced with DirectX 3 in 1996. DirectSound 3D is often abbreviated DS3D.
DirectSound3D allows software developers to write to a single standardized audio API instead of writing code for each audio card manufacturer.
In DirectX 5, DirectSound3D has the capability of having sound cards that use third party 3D audio algorithms accelerate DirectSound3D properly, through Microsoft-approved methods. This eliminate the need for separate 3D audio libraries.
[edit] Windows Vista
Because of Xbox and Windows Vista integration, Microsoft is actively pushing developers to migrate new applications to XACT. As a result of this, Windows Vista runs DirectSound in emulation mode on the Microsoft software mixer. The emulator does not have hardware abstraction, so there is no hardware DirectSound acceleration, meaning hardware and software relying on DirectSound acceleration will have degraded performance. In the case of hardware 3D audio effects, they will not be playable.
A solution is to use an OpenAL driver. However, this only works if the manufacturer provides an OpenAL driver for their hardware. As of 2007, only Sound Blaster X-Fi is supported by a pre-release driver that supports DirectSound HAL, under the name 'Creative ALchemy Project'.
