directsound

DirectSound is a legacy audio API within Microsoft's DirectX API suite that provides low-level access to sound devices on Windows. It enables applications to play and record audio with low latency by managing buffers and mixing audio data, either in software or via hardware-accelerated paths on compatible hardware.

Developers interact with DirectSound through dsound.dll, using interfaces such as IDirectSound, IDirectSoundBuffer, and, for 3D audio, IDirectSound3DListener and IDirectSound3DBuffer. A typical setup creates a primary buffer to define the output format (sample rate, channels, bit depth) and one or more secondary buffers containing audio data. Applications can write to secondary buffers and control playback, volume, and panning.

DirectSound also implements a 3D audio extension to render sound with position, velocity, and orientation in a virtual space, using the 3D listener and buffer interfaces and various properties like distance attenuation. It can take advantage of hardware mixing if the sound device supports it, otherwise it performs software mixing.

Over time, DirectSound has been superseded by newer Windows audio APIs. WASAPI provides low-latency audio streaming, and XAudio2 offers a modern, high-performance API for games. As a result, DirectSound is generally considered deprecated for new development, though it remains available for legacy applications and compatibility reasons.

See also: WASAPI, XAudio2, DirectX.