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Enhanced encoding tools for MPEG-4 audio lossless coding (ALS) international standard were developed, with the goal of improving compression performance of time-series biomedical data. The multichannel coding (MCC) tool of this standard exploits interchannel redundancies to reduce the bit rate. To improve compression performance with the MCC, we have devised a multichannel linear prediction tool, which achieves around a 0.1% better compression ratio than that of the conventional method. We have also developed an interchannel dependency analysis tool, which performs about 1000 times faster than the conventional one. By combining these tools, biomedical signals are losslessly compressed to about 1/3 in a practical computational load. Compressed biomedical data will be decoded even 100 years from now, because the bitstream still remains compliant with the MPEG standard.