Multiplexed audio data decoding apparatus and receiver apparatus

A multiplexed audio data decoder apparatus, for inputting a group of packets, each being formed by packetizing audio data sequences which are compressed and encoded and by multiplexing a plurality of those sequences, and for selectively decoding one audio data sequence which is designated by a user, comprising:

• a demultiplexer for extracting the one audio data sequence which is designated by the user from said group of packets depending upon a property or attribute information which each packet has, and further for extracting a method of the compression and encoding which is applied for compressing the audio data sequence from a header information which said each audio data sequence has;
• a first memory in which decoding process codes corresponding to said method of the compression and encoding;
• a digital signal processor for decoding the compressed audio data sequences in accordance with said decoding process codes, sequentially;
• a read-only memory, in which are accumulated a plurality of the decoding process codes, each corresponding to each one of said plural methods of the compression and encoding;
• and
• controller means for detecting change in said method of the compression and encoding, and for transferring the decoding process code corresponding to the method of the compression and encoding after being changed, from said read-only memory to said first memory, wherein
• said digital signal processor begins decoded process by using the decoding process code which is transferred to said first memory.