DSCAPS

The DSCAPS type describes the capabilities of a DirectSound device. Used by the DirectSound8.GetCaps method.

Syntax

Type DSCAPS
  lFlags As CONST_DSCAPSFLAGS
  lFreeHw3DAllBuffers As Long
  lFreeHw3DStaticBuffers As Long
  lFreeHw3DStreamingBuffers As Long
  lFreeHwMemBytes As Long
  lFreeHwMixingAllBuffers As Long
  lFreeHwMixingStaticBuffers As Long
  lFreeHwMixingStreamingBuffers As Long
  lMaxContigFreeHwMemBytes As Long
  lMaxHw3DAllBuffers As Long
  lMaxHw3DStaticBuffers As Long
  lMaxHw3DStreamingBuffers As Long
  lMaxHwMixingAllBuffers As Long
  lMaxHwMixingStaticBuffers As Long
  lMaxHwMixingStreamingBuffers As Long
  lMaxSecondarySampleRate As Long
  lMinSecondarySampleRate As Long
  lPlayCpuOverheadSwBuffers As Long
  lPrimaryBuffers As Long
  lReserved1 As Long
  lReserved2 As Long
  lTotalHwMemBytes As Long
  lUnlockTransferRateHwBuffers As Long
End Type

Members

lFlags

Device capabilities. Can be one or more of the constants from the CONST_DSCAPSFLAGS enumeration.

lFreeHw3DAllBuffers

Number of unallocated 3-D buffers.

lFreeHw3DStaticBuffers

Number of unallocated static 3-D buffers.

lFreeHw3DStreamingBuffers

Number of unallocated streaming 3-D buffers.

lFreeHwMemBytes

Size, in bytes, of the free memory on the sound card.

lFreeHwMixingAllBuffers

Number of unallocated buffers. On WDM drivers, this includes lFreeHw3DAllBuffers.

lFreeHwMixingStaticBuffers

Number of unallocated static buffers.

lFreeHwMixingStreamingBuffers

Number of unallocated streaming buffers.

lMaxContigFreeHwMemBytes

Size, in bytes, of the largest contiguous block of free memory on the sound card.

lMaxHw3DAllBuffers

Maximum number of 3-D buffers.

lMaxHw3DStaticBuffers

Maximum number of static 3-D buffers.

lMaxHw3DStreamingBuffers

Maximum number of streaming 3-D buffers.

lMaxHwMixingAllBuffers

Total number of buffers that can be mixed in hardware. This member can be less than the sum of lMaxHwMixingStaticBuffers and lMaxHwMixingStreamingBuffers. Resource tradeoffs frequently occur.

lMaxHwMixingStaticBuffers

Maximum number of static sound buffers.

lMaxHwMixingStreamingBuffers

Maximum number of streaming sound buffers.

lMaxSecondarySampleRate, lMinSecondarySampleRate

Maximum and minimum sample rate specifications that are supported by this device's hardware secondary sound buffers.

lPlayCpuOverheadSwBuffers

Description of the processing overhead, as a percentage of the central processing unit, needed to mix software buffers—those located in main system memory. This varies according to the bus type, the processor type, and the clock speed.

The unlock transfer rate for software buffers is zero because the data need not be transferred. Similarly, the play processing overhead for hardware buffers is 0 because the mixing is done by the sound device.

lPrimaryBuffers

Number of primary buffers supported. This value is always 1.

lReserved1, lReserved2

Reserved.

lTotalHwMemBytes

Size, in bytes, of the memory on the sound card that stores static sound buffers.

lUnlockTransferRateHwBuffers

Rate, in kilobytes per second, at which data can be transferred to hardware static sound buffers.

Remarks

Some audio cards may be unable to report accurately the number of available or free hardware buffers. This can happen, for example, when the card can play more sounds at lower sampling rates than at higher rates. In general, a nonzero value in any of the members relating to number of free hardware buffers signifies that at least one hardware resource of the appropriate type is available.