| 摘要 |
Method and apparatus of estimating available bandwidth for a media streaming network (such as Voice and Video over IP VVOIP) comprising a transmitting device 10 and a receiving device 20 whereby a media packet stream comprising media data is transmitted over the network 12 to the consumers receiving device 20; Bandwidth estimation comprises transmitting probe packet(s) comprising duplicate data of the media packet stream over the network and determining, during probe transmission, a measure of network bandwidth availability in dependence on one or more metrics associated with receiving the media packet stream at the receiving device. Such metrics may include network delay, packet reception gap, packet loss, network jitter and burst jitter appropriately weighted to provide a bandwidth factor. Employing useful duplicate data (or forward error correction data FEC) instead of junk test data aids the overall efficiency of the estimation process and reduces the effects of packet loss. Based on the measure, transmission may be stopped or if the result is favorable, the bit rate may be increased to enable video streaming. Transmission of the probe packets may be periodic at regular time intervals, the time period increasing when low bandwidth is encountered. A computer implementation of the method is also included. The transmitter may include a quality controller to initialize probe packets, whilst the bandwidth estimator monitors the network bandwidth. The receiver 10 transceiver 21 and bandwidth estimator 25 provide information regarding bandwidth estimation, whilst the jitter buffer 22 orders the received packet media data. Bandwidth estimation using duplicate probe packets may involve a round trip network delay from transmitter to receiver and back. |
