@param s allocated Swr context, not yet initialized
@param matrix remix coefficients; matrix[i + stride * o] is
the weight of input channel i in output channel o
@param stride offset between lines of the matrix
@return >= 0 on success, or AVERROR error code in case of failure.
Set a customized remix matrix.
@param s allocated Swr context, not yet initialized @param matrix remix coefficients; matrix[i + stride * o] is the weight of input channel i in output channel o @param stride offset between lines of the matrix @return >= 0 on success, or AVERROR error code in case of failure.