Content-immersive Subjective Quality Assessment in Long Duration 360-degree Videos.

This paper presents a comparison between three content-immersive methodologies to evaluate video quality: Absolute Category Rating (ACR) with unrepeated scenes, Single Stimulus Continuous Quality Evaluation (SSCQE), and Single Stimulus Discrete Quality Evaluation (SSDQE). Three tests were conducted with different participants assigned to each methodology to assess 360-degree video quality in an immersive communications context. Additionally, socioemotional aspects such as presence, attitude, or attention were measured for each condition. All three methodologies offer similar results in terms of video quality evaluation, and they all keep similar levels of social and spatial presence. Both SSCQE and SSDQE allow narrative and context while evaluating video quality, but SSDQE has less impact in participants' attention to the video content. These results suggest that it is possible to extend ITU-T P.919 with the support of long sequences with in-sequence SSDQE video quality evaluation, without significant impact on the socioemotional properties of the experience. This would result on a standard content-immersive method, methodology suitable for 360-degree video content, favoring the ecological validity of the subjective assessment tests.