waveOutSetPlaybackRate function (mmeapi.h)
The waveOutSetPlaybackRate function sets the playback rate for the specified waveform-audio output device.
Syntax
MMRESULT waveOutSetPlaybackRate(
HWAVEOUT hwo,
DWORD dwRate
);
Parameters
hwo
Handle to the waveform-audio output device.
dwRate
New playback rate setting. This setting is a multiplier indicating the current change in playback rate from the original authored setting. The playback rate multiplier must be a positive value.
The rate is specified as a fixed-point value. The high-order word contains the signed integer part of the number, and the low-order word contains the fractional part. A value of 0x8000 in the low-order word represents one-half, and 0x4000 represents one-quarter. For example, the value 0x00010000 specifies a multiplier of 1.0 (no playback rate change), and a value of 0x000F8000 specifies a multiplier of 15.5.
Return value
Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following.
| Return code | Description |
|---|---|
|
Specified device handle is invalid. |
|
No device driver is present. |
|
Unable to allocate or lock memory. |
|
Function isn't supported. |
Remarks
Changing the playback rate does not change the sample rate but does change the playback time. Not all devices support playback rate changes. To determine whether a device supports playback rate changes, use the WAVECAPS_PLAYBACKRATE flag to test the dwSupport member of the WAVEOUTCAPS structure (filled by the waveOutGetDevCaps function).
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | mmeapi.h (include Windows.h) |
| Library | Winmm.lib |
| DLL | Winmm.dll |