1. ABSTRACT In Digital Video Broadcasting for Handhelds (DVB-H), an audiovisual service is transmitted in time-slicing bursts to achieve power savings in receiving terminals. As in many other transmission schemes, the received data streams over DVB-H may contain residual transmission errors. The burst characteristics and appearance frequency of these transmission errors have an effect on the perceived audiovisual quality. The perceived quality is a significant factor in the end-user’s acceptance and the adoption of new mass products such as mobile television. This study investigated effects of four residual time-slice error rates on the overall subjective audiovisual quality. The quality was measured with subjective retrospective ratings of acceptance. Error rates of 1.7%, 6.9%, 13.8% and 20.7% were tested with clips from four popular television programs and evaluated by 30 participants. The results show that among the error rates simulated, error rates of 1.7% and 6.9% were experienced as acceptable, while error rates of 13.8% and 20.7% were perceived to be unacceptable. Simulation parameters: General ParametersParameter value MPE-FEC error rates[1.7%, 6.9%, 13.8%, 20.7%] MPE-FEC parameterParameter value Number of Rows512 Number of data columns191 Number of RS columns64 Video parameterParameter value Picture sizeQCIF Picture frame rate12.5 frames per second IDR refresh rateOnce every MPE-FEC frame Bit rate128 Kilobits per second Audio parameterParameter value Sampling rate16 Kilo hertz Bit rate32 Kilobits per second Simulation setup: H.264/AVC Encoder AAC Encoder Stream Mux Service Mux Service De-Mux Stream De-Mux 3GPP Converter AAC Decoder H.264/AVC Encoder AAC Encoder Stream Mux H.264/AVC Encoder AAC Encoder Stream Mux H.264/AVC Encoder AAC Encoder Stream Mux Stream De-Mux 3GPP Converter AAC Decoder Stream De-Mux 3GPP Converter AAC Decoder Stream De-Mux 3GPP Converter AAC Decoder DVB-H Channel Gilbert Elliot Simulator GOAL To study effects of residual time-slice error rates on the acceptance of overall subjective audiovisual quality RESEARCH METHOD Participants: 30 Aged18-45 years, equally stratified by age, gender, <20% professionals, normal/ corrected-to-normal visual acuity, colour vision and normal hearing Test procedure:Retrospective ratings of acceptance Pre-test: Sensory tests, demographic survey Test: Anchoring & training, test with continuous assessment and retrospective ratings Post-test: Content survey, interview Contents: - Potential for mobile TV, popular -Variations in the levels of spatial details, temporal motion and audiovisual characteristics - The length of the clips: 60s Presentation of test material Laboratory environment: ITU-T P.920 Device: Nokia 6630 with headphones Viewing distance: 44 cm Audio loudness level: 75 dBA 3 repetitions played in random order RESULTS Acceptance of different error rates (McNemar test): Acceptable: Error rates 1.7% and 13.8% Unacceptable:Error rates 13.8% and 20.7% Comparisons All contents Animation Music video NewsSport 1.7% vs. 6.9%p<0.001 p<0.05 1.7% vs. 13.8%p<0.001 1.7% vs. 20.7%p<0.001 6.9% vs. 13.8%p<0.001 6.9% vs. 20.7%p<0.001 13.8% vs. 20.7%p<0.01p<0.05p>0.05, ns 1.7%6.9%13.8%20.7% ContentMediaNMeanVarNMeanVarNMeanVarN Mea n Var Animation Audio Video 2121 0.54 1.28 0.08 0.00 5454 0.32 1.02 0.02 0.47 14 7 0.31 1.78 0.06 0.87 22 10 0.31 1.69 0.02 1.22 Music Audio Video 3131 0.34 1.36 0.01 0.00 5353 0.29 1.12 0.02 0.21 14 9 0.31 1.13 0.06 0.19 22 15 0.31 1.10 0.02 0.31 News Audio Video 2121 0.54 1.44 0.08 0.00 5454 0.32 1.00 0.21 0.13 14 7 0.30 1.85 0.05 2.20 22 10 0.31 1.62 0.02 1.46 Sports Audio Video 2121 0.54 1.28 0.08 0.00 5454 0.32 1.00 0.13 0.34 15 7 0.28 2.00 0.05 0.68 22 10 0.30 1.78 0.02 0.53 Error pattern details: DISCUSSION AND CONCLUSIONS Acceptance threshold lies between time-slice error rates of 6.9% and 13.8% Acceptance is affected by number of errors and error characteristics (duration, modalities) S. Jumisko-Pyykkö (a), Vinod Kumar M.V. (a), M. Liinasuo (b), M. M. Hannuksela (b) (a) {@tut.fi, Tampere University of Technology}; (b) {@nokia.com, Nokia Research Center} ACCEPTANCE OF AUDIOVISUAL QUALITY IN ERRONEOUS TELEVISION SEQUENCES OVER A DVB-H CHANNEL