Supporting a switch between audio coder modes

The invention relates to a supporting method for digital signal, the first encoder mode and second encoder model can be used for code the audio signal each component. The second encoder mode of based on real need is from each light information encoding the part of the first control device, and based on with a information overlapped signal control each part of the second coding device of apparatus part, realized each part of code. From the first encoder mode conversion to the second encoder), a bus used for coding the first coding model the audio signal the first part. The part which is used for generating then could by the second coding model code the end part artificial overlapped signal.