1. A method for multi-mode video event indexing, the method comprising: determining by a processor a quality of object distinctiveness with respect to images from a video stream input; in response to the determined level of detected quality of object distinctiveness meeting a threshold level of quality, the processor selecting a high-quality analytic mode from a plurality of video analytics modes and applying the high-quality analytic mode to the video input images to determine object activity within the video input images; and in response to the determined level of detected quality of object distinctiveness not meeting the threshold level of quality, the processor selecting a low-quality analytic mode from the plurality of video analytics modes and applying the low-quality analytic mode to the video input images to determine object activity within the video input images; and wherein the determining the quality of object distinctiveness with respect to the video input images comprises determining an amount of scene illumination in the video input images, the threshold level of quality is an amount of scene illumination, the high-quality analytic mode is a strong-shadow analytic mode that provides for object activity detection by removing strong shadows from the scene images, and the low-quality analytic mode is a low-light analytic mode that is different from the high-quality analytic mode and parses the video images for object activity detection without removing shadows from the scene images.