Multimedia applications have become the prime source of Internet traffic in recent years due to high bandwidth offered by almost all access mechanisms. This highlights the need of intense research efforts to improve the already demanding user perception levels for high-performance video delivery networks. Quality of Experience (QoE) based metrics are often used to quantify user satisfaction levels regarding an application or service. In this paper, we have analyzed the impact of variable frame sizes at link layer with different packet loss scenarios to evaluate the performance degradation of H.264 based live video streams from the end user perspective using subjective tests. We have focused on both subjective and objective quantitative measures to analyze the myth that smaller packets provide better quality in error-prone networks. We found that this assumption may not be true for some cases with a considerable packet loss ratio. Moreover, we observed that full-reference video assessment software like PEVQ predicts QoE to an acceptable extent, which allows cutting cost and effort coming with subjective evaluations.