Using Hardware Mixing

Most sound cards support some level of hardware mixing if there is a DirectSound driver for the card. The following tips allow you to make the most of hardware mixing.

• At run time, use the IDirectSound::GetCaps method to determine what formats are supported by the sound-accelerator hardware and use only those formats if possible.
• Create sound buffers first for the sounds you use the most. There is a limit to the number of buffers that can be mixed by hardware.
• To force a buffer to be created in hardware, specify the DSBCAPS_LOCHARDWARE flag in the dwFlags member of the DSBUFFERDESC structure. If you do this and resources for hardware mixing are not available, the IDirectSound::CreateSoundBuffer method will fail.
• Use voice management to enable DirectSound to assign buffers to hardware resources when they are available, and to force termination of less important buffers in order to free hardware resources. For more information, see Dynamic Voice Management.