In this paper, we study the problem of Transmission Distortion-optimized Unequal Loss Protection (TD-ULP) under rate constraints for non-scalable video transmission over packet erasure channels. Based on a packet-level transmission distortion modeling scheme, we estimate the amount of contribution of each video packet to the reconstructed video quality, which defines the priority level of each packet. Unequal amounts of protections are then allocated to different video packets according to their priority levels as well as the dynamic channel conditions. The optimal ULP resource allocation is formulated as a constrained nonlinear optimization problem. An evolutionary algorithm based on Particle Swarm Optimization (PSO) is developed to obtain the optimal resource allocation. Our extensive experimental results demonstrate the effectiveness of the proposed TD-ULP scheme, which outperforms existing methods by up to 2dB gain in reconstructed video quality. 1*