Encoding and decoding methods are provided. An information object is encoded according to a preset encoding scheme. A preset set of bits is selected from the encoded information object and the selected set of bits is output as a sample. A control packet including information on a sample number is generated. The sample is assembled with the control packet. The sample is modulated into a sound signal according to a preset scheme. An input sound signal is demodulated according to the preset scheme. Sample bits and control packet bits containing information of the sample are separated from each other in demodulated received bits. Address information corresponding to each bit of the sample is generated according to the control packet. A soft decision of the sample bits is summed for each piece of the generated address information. A sample decoding of the summed soft decision of the sample bits is performed.