| 摘要 |
<p>A communications device 2A, configured so as to be able to communicate using any one of several coders/decoders (codecs) (A1, A2, M1, M2) during a communication session, selects a subset of the codecs 90 (A2, M1) based on at least one operative condition 88. The device conducts a signalling process 92 to determine a codec from the subset for use during the session. The operative condition(s) may be one or more of the number of dropped packets, the bandwidth of the connection, the communications protocol used for the connection, a quality of service (QoS) parameter of the connection and a measure of the availability of processing resources in the communications device. If a suitable codec from the subset cannot be agreed with the other communications device 2B, then it is determined whether a transcoding service 116 is available. If so, an extended list of codecs is offered 104, the extended list including codecs which are available if transcoding is used 102.</p> |
