1. A method for multi-mode video event indexing, the method comprising: determining by a processor a level of density of foreground object activity detected with respect to video input images from a video stream input relative to an entirety of the image; in response to the determined level of density of the detected foreground object activity meeting a threshold density value, the processor selecting from a plurality of video analytics modes and applying an object tracking-based analytic mode to the detected foreground object activity of the video input images to track a foreground object; and in response to the determined level of density of the detected foreground object activity not meeting the threshold density value, the processor selecting from the plurality of video analytics modes and applying a non-object tracking-based analytic mode to the detected foreground object activity of the video input images to determine object movement from extracted foreground object appearance attributes without tracking the foreground object.