Subjective Quality Assessment of Longer Duration Video Sequences Delivered Over HTTP Adaptive Streaming to Tablet Devices

Abstract

Abstract-HTTP Adaptive Streaming facilitates video streaming to mobile devices connected through heterogeneous networks without the need for a dedicated streaming infrastructure. By splitting different encoded versions of the same video into small segments, clients can continuously decide which segments to download based on available network resources and device characteristics. These encoded versions can, for example, differ in terms of bitrate and spatial or temporal resolution. However, as a result of dynamically selecting video segments, perceived video quality can fluctuate during playback which will impact end-users' Quality of Experience. Subjective studies have already been conducted to assess the influence of video delivery using HTTP Adaptive Streaming to mobile devices. Nevertheless, existing studies are limited to the evaluation of short video sequences in controlled environments. Research has already shown that video duration and assessment environment influence quality perception. Therefore, in this article, we go beyond the traditional ways for subjective quality evaluation by conducting novel experiments on tablet devices in more ecologically valid testing environments using longer duration video sequences. As such, we want to mimic realistic viewing behaviour as much as possible. Our results show that both video content and the range of quality switches significantly influence end-users' rating behaviour. In general, quality level switches are only perceived in high motion sequences or in case switching occurs between high and low quality video segments. Moreover, we also found that video stallings should be avoided during playback at all times.Index Terms-Quality of Experience (QoE), Subjective video quality assessment, HTTP adaptive streaming, Mobile video, Tablet devices.

Perceptual Quality of HTTP Adaptive Streaming Strategies: Cross-Experimental Analysis of Multi-Laboratory and Crowdsourced Subjective Studies

“…In addition, the impact of these factors in up-switching (increasing the quality) and down-switching (decreasing the quality) should be considered. The results presented in [5], [8], [9] showed that inserting intermediate levels between quality drops was favorable for the perceived quality, compared to switching directly to the target quality level. However, the results presented in [10] showed that, although down-switching is generally considered annoying, abrupt up-switching might even increase the QoE as users might be happy to notice the visual improvement.…”

On subjective quality assessment of adaptive video streaming via crowdsourcing and laboratory based experiments

“…Various observations were made including the preference of constant bitrate over frequently changing bitrate and a slow drop to the lower quality over oscillating bitrates. Staelens et al [37] performed a subjective study for long duration videos on tablet devices for investigating the impact of quality switches due to adaptive streaming. They observed that users mainly perceive the change of quality from the highest to the lowest levels and high to medium quality changes remain largely unnoticeable.…”

Impact of packet loss on the perceived quality of UDP-based multimedia streaming: a study of user quality of experience in real-life environments

“…Another possible solution is presented by Staelens et al in [16], where the authors implemented a subjective quality assessment methodology into the application used for presenting video content on mobile devices. The authors were the owners of the mobile devices, and the prepared test sequences were stored locally on the devices.…”

“…During the streaming sessions, the button was pressed by the test subjects when they wanted to indicate noticing the frame freeze video artifact. Note that the study also assumed streaming of the content to the subjects' devices for rating and, similar to [16], the used methodology revealed the purpose of the test to the subjects.…”