Adjusting Speed, Volume, and Zoom
The speed, volume, and zoom macros provide the functionality of the View
, and Speed
commands on the MCIWnd menu. The macros described in this section are
generally used with video and other devices that display images during playback.
Some devices support multiple playback speed changes. You can set the playback
speed for these devices by using the MCIWndSetSpeed
macro. This macro defines the playback speed as 1000. Higher values indicate
faster speeds. Lower values indicate slower speeds.
You can retrieve the current playback speed by using the MCIWndGetSpeed
macro. This macro uses the same values and range as those used by MCIWndSetSpeed
Some devices support volume changes. You can adjust or set the volume by using
macro. This macro defines the normal volume level as 1000. Higher values
indicate louder volumes. Lower values indicate quieter volumes.
You can retrieve the current volume level by using the MCIWndGetVolume
macro. This macro uses the same numerical values and range as those used by MCIWndSetVolume
For devices that use a playback window, MCIWnd supports a zoom feature that
sets the size of the playback image. You can set the playback image size by using
macro. The macro redefines the playback image size while maintaining a
constant aspect ratio for the image. The zoom value is defined as a percentage of the
original image size. Thus, 100 represents the original image size, 50
indicates the image shown is half its original size, and 200 indicates that the image
shown is twice its original size.
You can retrieve the current zoom value by using the MCIWndGetZoom
macro. This macro uses the same values and range as those used by MCIWndSetZoom
The standard MCI CD audio and waveform-audio drivers do not support volume
or speed changes.
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