Patent ID: 8504184

Claim:
A combination device that combines a plurality of coded bitstreams transmitted from a plurality of sites, the plurality of coded bitstreams each including a downmix sub-stream and a parameter sub-stream, the downmix sub-stream being generated by down-mixing a plurality of input audio signals and having a total number of signals that is less than a total number of signals in the plurality of input audio signals, and the parameter sub-stream being to be used to decode the downmix sub-stream into the plurality of input audio signals which have the total number of signals that is more than the total number of signals in the downmix sub-stream, said combination device comprising: a detection unit configured to detect an active coded bitstream from the plurality of coded bitstreams within a predetermined time period, the active coded bitstream being a coded bitstream that has a sound volume that is larger than a predetermined threshold value; a first combining unit configured to combine, from among a plurality of downmix sub-streams, only plural downmix sub-streams included in plural active coded bitstreams, so as to generate a combined downmix sub-stream; a second combining unit configured to combine, from among a plurality of parameter sub-streams, only plural parameter sub-streams included in the plural active coded bitstreams, so as to generate a combined parameter sub-stream; and a transmission unit configured to transmit, to the plurality of sites, a combined bit stream that includes the combined downmix sub-stream and the combined parameter sub-stream; wherein said second combining unit includes a parameter basis unifying unit configured to convert different parameter presentation bases of the plural parameter sub-streams to a single unified parameter presentation basis, and generate plural unified parameters based on the single unified parameter presentation basis, when the plural parameter sub-streams are expressed by the different parameter presentation bases, and wherein said second combining unit is configured to combine the plural unified parameters so as to generate the combined parameter sub-stream.