How to use external video devices

QTM can record video data, including the sound, together with the motion capture data. This data is only for documentation purposes and are not used in the calculation of 3D data. The video source can be either via DirectShow (Blackmagic Design cards or DV/webcam devices), see respectively chapters Video capture with Blackmagic Design cards and DV/webcam devices.

The video capture via DirectShow starts and stops in synchronization with the motion capture. The synchronization is done via Windows OS, therefore exact synchronization cannot be guaranteed. It is, however, within a quarter of a second. It is possible to change the offset of the video to get a more accurate synchronization, see chapter Video offset.

The capture rate of the video data depends on the hardware of the video device, on the settings of the video device and on the general performance of the measurement computer that QTM runs on. To set the settings of the video device, right-click in the view of the video camera in a 2D view window, in the preview mode, to open the View window menu. Click Video camera settings to open the dialog with settings. For information about the settings see the manual of the video device.

The recorded video data will be saved as an AVI file in the same folder that is selected for the capture file (QTM file) and it will have the same name as the capture file. It can be played in any media player that supports the AVI format as well as viewed in QTM together with the motion capture data. For more information about the display of video data, see chapter External video devices in 2D view.

The following chapters describe how to use external video sources with QTM.