DirectSound

DirectSound is a deprecated software component of the Microsoft DirectX library for the Windows operating system, superseded by XAudio2. It provides a low-latency interface to sound card drivers written for Windows 95 through Windows XP and can handle the mixing and recording of multiple audio streams. DirectSound was originally written for Microsoft by John Miles. Besides providing the essential service of passing audio data to the sound card, DirectSound provides other essential capabilities such as recording and mixing sound, adding effects to sound (e.g., reverb, echo, or flange), using hardware accelerated buffers in Windows 95 through XP, and positioning sounds in 3D space. DirectSound also provides a means to capture sounds from a microphone or other input and controlling capture effects during audio capture. After many years of development, today DirectSound is a mature API, and supplies many other useful capabilities, such as the ability to play multichannel sounds at high resolution. While DirectSound was designed to be used by games, today it is used to play audio in many audio applications. DirectShow uses DirectSound's hardware audio acceleration capabilities if the sound card's hardware audio acceleration capabilities exist and are exposed by the audio driver. DirectSound is a user mode API that provides an interface between applications and the sound card driver, enabling applications to produce sounds and play back music. DirectSound was considered revolutionary when it was introduced in 1995, as it featured multiple simultaneous audio streams and allowed several applications to access the sound card simultaneously. Before that, the game developers were required to implement their own audio rendering engine in software. DirectSound provides sample rate conversion and sound mixing (volume and pan) for an unlimited number of audio sources; however, the practical limits are the number of hardware audio sources and the performance of software mixers.