Subjective evaluation of the effects of packet loss on HEVC encoded video streams

The emerging High Efficiency Video Coding standard (HEVC) will bring the benefit of delivering the same statistical quality at about half of the bandwidths required in the current H.264/AVC standard. Such significantly higher compression efficiency of HEVC will, however, potentially lead to higher sensitivity to packet loss and thus have a great impact on the users of portable consumer devices such as smartphones and tablets when delivering HEVC encoded video over loss-prone networks, thereby adversely affecting the user's quality of experience (QoE). Existing subjective evaluations of the perceptual quality of HEVC have focused on its performance in loss-free environments. In this work, we empirically transmit HEVC streams over a hybrid wired/wireless network at typical (UK) mobile broadband speeds under a range of packet loss conditions, using typical smartphone and tablet resolutions. Our subjective evaluation experiments quantify the effect, on perceptual quality, of packet loss in HEVC streams and establish a packet loss rate threshold of 3% beyond which users find poor perceptual quality has a detrimental effect on their QoE. Furthermore, we employ two error concealment schemes to mitigate the impact of packet loss/corruption and investigate their effectiveness on users' QoE.