With the growing demand for video analysis on mobile devices, object tracking has demonstrated to be a suitable assistance to object detection under the Tracking-By-Detection (TBD) paradigm for reducing computational overhead and power demands. However, performing TBD with fixed hyper-parameters leads to computational inefficiency and ignores perceptual dynamics, as fixed setups tend to run suboptimally, given the variability of scenarios. In this article, we propose SmartTBD, a scheduling strategy for TBD based on multi-objective optimization of accuracy-latency metrics. SmartTBD is a novel deep reinforcement learning based scheduling architecture that computes appropriate TBD configurations in video sequences to improve the speed and detection accuracy. This involves a challenging optimization problem due to the intrinsic relation between the video characteristics and the TBD performance. Therefore, we leverage video characteristics, frame information, and the past TBD results to drive the optimization problem. Our approach surpasses baselines with fixed TBD configurations and recent research, achieving accuracy comparable to pure detection while significantly reducing latency. Moreover, it enables performance analysis of tracking and detection in diverse scenarios. The method is proven to be generalizable and highly practical in common video analytics datasets on resource-constrained devices.