Forgiveness effect in subjective assessment of packet video

Experimental results are reported of the subjective assessment of picture impairments due to cell loss in asynchronous transfer mode (ATM) networks. It is shown that the CCIR 5-grade impairment scaling method is suitable for the kind of impairment found in overload conditions. The results serve to quantify the ´forgiveness´ effect, which influences the subjective quality of the decoded pictures. Some suggestions are made as to how this can be taken into consideration in packet video quality assessment.