Hardware and Software Sound Buffers

A hardware sound buffer has its mixing performed by a hardware mixer located on the sound device. A software sound buffer has its mixing performed by the system central processing unit. In most cases, your application should simply specify whether the buffer is static or streaming; DirectSound locates the buffer in hardware or software as appropriate.

If your application must explicitly locate buffers in hardware or software, however, you can specify either the DSBCAPS_LOCHARDWARE or DSBCAPS_LOCSOFTWARE flag in the DSBUFFERDESC structure. If the DSBCAPS_LOCHARDWARE flag is specified and there is insufficient hardware memory or mixing capacity, the buffer creation request fails. Also, most existing sound devices do not have any hardware memory or mixing capacity, so no hardware buffers can be created on these devices.

You can determine the location of a sound buffer by using the IDirectSoundBuffer::GetCaps method and checking the dwFlags member of the DSBCAPS structure for either the DSBCAPS_LOCHARDWARE or DSBCAPS_LOCSOFTWARE flags. One or the other is always specified.