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A Study on Quality Improvement of Ultra Multi-channel Audio Coding using Residual Signal

  • Journal of Knowledge Information Technology and Systems
  • Abbr : JKITS
  • 2019, 14(1), pp.53-62
  • DOI : 10.34163/jkits.2019.14.1.006
  • Publisher : Korea Knowledge Information Technology Society
  • Research Area : Interdisciplinary Studies > Interdisciplinary Research
  • Received : December 6, 2018
  • Accepted : February 8, 2019
  • Published : February 28, 2019

Kwangki Kim 1

1나사렛대학교

Accredited

ABSTRACT

The conventional ultra multi-channel audio coding (UMAC) based on playback space segmentation divides the playback space into five spaces and separately encodes input signals for each space using the encoding module for each space. Generated 5 down-mix signals for each space are encoded using a 5.1 channel audio coder. Therefore, the UMAC requires only one or two coders, so that the bit rate and complexity are very low, enabling realistic sound service in wired/wireless network, communication, and mobile environments. However, since the UMAC restores the ultra multi-channel signal using only the down-mix signal and the power ratio parameters extracted from the 28 sub-bands, deterioration of the sound quality can not be avoided. In this paper, we propose an enhanced UMAC (E-UMAC) to improve the quality of reconstructed signal by using residual signal which compensates the difference between original signal and reconstructed signal to solve the problem of sound quality deterioration of the UMAC. According to the proposed method, a coding module for each playback space is changed to extract a residual signal and add a process of restoring the input signals using the residual signal. Moreover, the overall coding structure is changed so that one residual signal is extracted for the 2-channel input. For the verification, we coded 10.2 channel audio contents using the implemented E-UMAC and performed the bit-rate measurement and the sound quality evaluation. The effectiveness of the proposed E-UMAC was validated from experimental results that the bit-rate is increased by about 44% compared with the UMAC but the sound quality of the reconstructed signal is greatly improved.

Citation status

* References for papers published after 2023 are currently being built.

This paper was written with support from the National Research Foundation of Korea.