Estimating the impact of single and multiple freezes on video quality

This paper studies the impact of freezing of video on quality as experienced by users. Two types of freezes are investigated. First a freeze where the image pauses, so no frames were lost (frame halt). In the second type of freeze, the image freezes and skips that part of the video (frame drop). Measuring Mean Opinion Score (MOS) was done by subjective tests. Video sequences of 20 seconds were displayed for four types of content, to a total of 23 test subjects. We conclude there is no difference in the perceived quality between frame drops and frame halts. Therefore one model for single freezes was constructed. According to this model the acceptable freezing time (MOS>3.5) is 0.36 seconds.