waveOutSetPlaybackRate
The waveOutSetPlaybackRate function sets the playback rate for the specified waveform-audio output device.
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 Values
Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following.
| Value | Description |
| MMSYSERR_INVALHANDLE | Specified device handle is invalid. |
| MMSYSERR_NODRIVER | No device driver is present. |
| MMSYSERR_NOMEM | Unable to allocate or lock memory. |
| MMSYSERR_NOTSUPPORTED | 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
** Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
** Windows 95/98/Me:** Included in Windows 95 and later.
** Header:** Declared in Mmsystem.h; include Windows.h.
** Library:** Use Winmm.lib.
See Also
Waveform Audio, Waveform Functions, WAVEOUTCAPS, waveOutGetDevCaps