||r/w||the number of channels of the source|
||r/w||the channel positions of the source|
||r/w||the matrix coefficients.|
||r/w||the number of channels of the destination|
||r/w||the channel positions of the destination|
Extra buffer metadata describing audio downmixing matrix. This metadata is attached to audio buffers and contains a matrix to downmix the buffer number of channels to channels.
matrix is an two-dimensional array of to_channels times from_channels coefficients, i.e. the i-th output channels is constructed by multiplicating the input channels with the coefficients in matrix[i] and taking the sum of the results.