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waveOutSetPlaybackRate function

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 codeDescription
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

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Mmsystem.h (include Windows.h)

Library

Winmm.lib

DLL

Winmm.dll

See also

Waveform Audio
Waveform Functions

 

 

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