| Parameters | DWORD lParam1 | The following standard and command-specific flags apply to all devices supporting this command: |
| MCI_NOTIFY | Specifies that MCI should post the MM_MCINOTIFY message when this command completes. The window that receives this message is specified in the dwCallback field of the data structure identified by lParam2. | |
| MCI_TEST | Queries the device to determine if it can execute the command. The device returns an error if it is incapable of executing the command. It returns no error if it can handle the command. MCI returns control to the application without executing the command. | |
| MCI_WAIT | Specifies that the operation should finish before MCI returns control to the application. | |
| MCI_DGV_MONITOR_METHOD | Specifies that a constant indicating the method of monitoring is included in the dwMethod field of the data structure identified by lParam2. | |
| When used with MCI_DGV_MONITOR_INPUT this option selects the method of monitoring. Typically, different monitoring methods have different implications on how the hardware is used. The default monitoring method is selected by the device. Use one of the following constants to indicate the method of monitoring: |
| MCI_DGV_METHOD_DIRECT | Specifies that the device should be configured for optimum display quality during monitoring. Direct monitoring might be incompatible with motion-video recording. | |
| MCI_DGV_METHOD_POST | Specifies that the device should show the external input after compression. Post monitoring supports motion-video recording. | |
| MCI_DGV_METHOD_PRE | Specifies that the device should show the external input prior to compression. |
| MCI_DGV_MONITOR_SOURCE | Specifies that a constant indicating the monitor source is included in the dwSource field of the data structure identified by lParam2. Use one of the following constants to indicate the source: |
| MCI_DGV_MONITOR_INPUT | Specifies that the external input is the presentation source. A play in progress is first paused before the input is selected. If MCI_SETVIDEO is enabled using the MCI_ON flag, this flag displays a default hidden window. Device drivers might limit what other device instances can do while monitoring input. | |
| MCI_DGV_MONITOR_FILE | Specifies that the workspace is the presentation source. (This is the default source.) If this option is used during recording, the recording pauses. If this command changes the presentation source, recording or playing stops and the current position is the value returned by the MCI_STATUS command for the start position. | |
| LPMCI_DGV_MONITOR_PARMS lParam2 | Specifies a far pointer to the MCI_DGV_MONITOR_PARMS data structure. |
| Return Value | Returns zero if successful. Otherwise, it returns an MCI error code. | |
| Comments | The default presentation source is the workspace. Switching the presentation source switches all audio and video in the source. The presentation source automatically switches to the workspace for the MCI_PLAY, MCI_PAUSE, MCI_STEP, and MCI_SEEK commands and for the MCI_CUE command when the MCI_DGV_CUE_OUTPUT flag is specified. The record command does not automatically switch presentation sources. This lets applications not show the video while it is being recorded. |