Quality of MPEG transfer over ATM DBR service class with effective bandwidth usage

The highly bursty nature of MPEG wastes the bandwidth when it is applied to ATM deterministic bit rate (DBR) service class. Our approach is to adjust the output rate of the encoder to the allocated bandwidth. Using this approach, the uncertainty in predicting the maximum picture size of the stream can be avoided. We evaluate how such a rate adaptation affects the video quality in terms of the signal to noise ratio (SNR) and mean opinion score (MOS). For the rate adaptation method, we consider the priority control method, space reduction method, time reduction method and the bandwidth renegotiation method. Through experimental results, it is shown that the space reduction method is useful for real-time transmission, while the time reduction method can be applicable if the application can tolerate its effect on the transfer delay between source and destination.