How annoying is the slowdown of video sequences?


Testing the effect of slowdown on scenes with different motion intensity

Summary

In this experiment, we considered short (~2sec) scenes from various well-known sequences, with different motion intensity each. In particular, we have considered the 4 first scenes from Table I (in the paper). We have slowed down the playout rate of all scenes by different amounts. Our goal is to evaluate how annoying is the slowdown as a function of (i) the amount of slowdown and (ii) the motion intensity of the scene.

Rationale

We expect that the larger the slowdown and the more motion in the scene, the more annoying the result. The purpose of this informal test is to confirm this hypothesis, which is central to the paper.

Sequence/Playout rate 30fps 25fps 20fps 15fps
Scene from Foreman original (rate=5) 1 2 3
Scene from Carphone original (rate=5) 4 5 6
Scene from Mother original (rate=5) 7 8 9
Scene from Grandma original (rate=5) 10 11 12

Instructions

First view the original video clips. These clips (at the playout rate of 30fps) are considered perfect and are rated with the highest quality 5. Then view the modified video clips row by row (in the order indicated by the numbers). View and rate all the other clips with a grade 1,2,3,4,5.

Testing how much the joint control helps - considering the entire sequence

In this test, we have considered a longer sequence, the one that consists of the concatenation of the 10 short scenes of Table I (in the paper). We have generated one realization of the wireless channel (using the parameters specified in section IV.A of the paper). We have simulated the transmission of the original sequence over this channel, first without any control and then with our joint control, and we have reconstructed the sequences that would be played out at the receiver. View and rate those sequences in a scale from 1 to 5, considering the original sequence perfect (5). (Note: each sequence is 50M each, so this may take a little longer to download.)
Email your ratings to athina@uci.edu. Thank you for the help!
Sept 9th 2007