When a file or device is associated with an MCIWnd window, the playback position is initially set at the start of the content, regardless of the media type. During playback, the playback position moves linearly through the content and, if playback is uninterrupted, eventually reaches the end of the content. If an interruption occurs, the current playback position is the location at which playback was stopped or paused.
You can retrieve the locations for the beginning and end of the content by using the MCIWndGetStart and MCIWndGetEnd macros. You can determine the length of the content by subtracting the value returned by MCIWndGetStart from the value returned by MCIWndGetEnd, or by using the MCIWndGetLength macro. You can retrieve the current playback position by using the MCIWndGetPosition macro, or you can retrieve the playback position as a null-terminated string by using the MCIWndGetPositionString macro.
To change the current playback position, use the MCIWndHome, MCIWndEnd, and MCIWndSeek macros. You can move the playback position to the start of the content by using MCIWndHome or to the end of the content by using MCIWndEnd. Use MCIWndSeek to move the playback position to any location in the content.
You can also step through the content by using the MCIWndStep macro. Beginning from the current playback position, this macro moves the playback position forward or backward by a specified increment.
Note The units used to specify position vary among the different media types and devices. For example, the playback position for AVI files used by the MCIAVI device is measured in frames; the playback position for CD audio, waveform-audio, and MIDI files is measured in milliseconds.
Devices for other media types and third-party devices might use other units. For information about determining these units, see Playback Enhancements.