6.5.1 Transcoding Matrix

In the case where an incoming Channel Based stream needs transcoding into an outgoing Channel Based stream which has less channels, the IO Matrix is used to re-map the output format by dropping some of the input channels. Similarly, if the transcode results in a format with more channels than the input format, the IO Matrix is used to remap inputs to outputs. This is not strictly Transcoding or decoding but is a useful tool to have in certain format changing scenarios. To properly up mix or down mix, it is advisable to use a room to take the virtual source of one format, and output with the desired end format.