Lossless audio encoding method, lossless audio encoding device, lossless audio decoding method, lossless audio decoding device, and recording medium

摘要

Provided are a lossless audio encoding/decoding method and apparatus. The lossless audio encoding method includes converting an audio signal in a time domain into an audio spectral signal with an integer in a frequency domain, mapping the audio spectral signal in the frequency domain to a bit plane signal according to its frequency, and losslessly encoding binary samples of bit planes using a probability model determined according to a predetermined context. The lossless audio decoding method includes extracting a predetermined lossy bitstream that is lossy encoded and an error bitstream from error data by demultiplexing an audio bitstream, the error data corresponding to a difference between lossy encoded audio data and an audio spectral signal with an integer in a frequency domain; lossy decoding the extracted encoded lossy bitstream; losslessly decoding the extracted error bitstream; restoring the original audio frequency spectral signal using the decoded lossy bitstream and error bitstream; and restoring the original audio signal in a time domain by performing inverse integer time-to-frequency conversion on the audio spectral signal. Accordingly, it is possible to encode/decode an audio signal at the optimum compression rate using a probability model based on the statistical distribution of integer MDCT coefficients, rather than the substantial distribution of integer MDCT coefficients. Also, it is possible to compress an audio signal at the optimum compression rate using context-based encoding better than when using BPGC.