waveOutGetPlaybackRate
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4/8/2010
This function queries the current playback rate setting of a waveform output device.
Syntax
MMRESULT waveOutGetPlaybackRate(
HWAVEOUT hwo,
LPDWORD pdwRate
);
Parameters
- hwo
Handle to the waveform-audio output device.
pdwRate
Pointer to a variable to be filled with the current playback rate. The playback rate 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 of the variable 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
One of the values described in the following table is returned.
| Value | Description |
|---|---|
MMSYSERR_NOERROR |
Success. |
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 is not 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
| Header | mmsystem.h |
| Library | coredll.lib |
| Windows Embedded CE | Windows CE 2.0 and later |
| Windows Mobile | Windows Mobile Version 5.0 and later |