Method for encoding/decoding of embedding the ancillary data in mpeg-4 bsac audio bitstream and apparatus using thereof

The present invention additionally as information about the insertion of the MPEG-4 Audio BSAC coding / decoding method and apparatus, the encoding method quantizes change the audio signal into a frequency domain signal counts the number of data bits, and obtaining the number of available bits per layer step of modifying the number of available bits per layer considering the size of ancillary information; Comprising the step of encoding a hierarchical unit, add the additional information to the bit stream, the encoding apparatus includes a quantization processor; It means available bit calculator by layer; It means for modifying the number of available bits per layer obtaining the size of ancillary information; And encoding according to the number of available bits per layer the audio data includes bit packing portion for adding additional information. The decoding method decodes the header, and obtains a bit-stream hierarchy, the step of determining a highest layer frame size and the size difference between the size of the additional information; And extracting the additional information by the size of the additional information, and a step of decoding the audio data, the decoding apparatus includes a bit unpacking unit for decoding a header; It means for obtaining a hierarchical structure of the bitstream; Additional information calculation unit for the size and frame size difference between the top layer to the size of the additional information; The additional information extracting unit which extracts the additional information by the size of the additional information; It characterized in that it comprises and audio decoder for decoding audio data up to the top layer portion. According to the present invention, it is possible to improve the meta data or sound quality of the audio content if the service through the BSAC by embedding the additional data.