A Practical Code Rate Decision Scheme Based on Playable Bitrate Model for Error-Resilient Joint Source-Channel Coding

Yo-Won JEONG  Kwang-Deok SEO  Kyu Ho PARK  

IEICE TRANSACTIONS on Communications   Vol.E94-B   No.3   pp.676-685
Publication Date: 2011/03/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.676
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Information and Communication Technologies for Next-generation Mobile Multimedia Life)
joint source-channel coding,  code rate decision,  error-resilient video coding,  forward error correction,  

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Joint source-channel coding (JSCC) is a method to jointly allocate the given total transmission bitrate to the source coding and channel coding to maximize the video quality at the receiving end. In this paper, we propose a practical model for efficiently determining a near-optimal code rate for JSCC in real-time video communications. The conventional code rate decision schemes using analytical source coding distortion model and channel-induced distortion model are usually complex, and typically employ the process of model parameter training which involves potentially high computational complexity and implementation cost. To avoid the complex modeling procedure, we introduce a very simple video quality model based on the playable bitrate which is defined as the total bit amount per unit time that is not affected by the channel loss during transmission including correctly recovered bits by the channel decoder. Because the video quality at the receiving end is clearly commensurate with the playable bitrate, we can easily determine the quality-oriented near-optimal code rate by finding the code rate that maximizes the playable bitrate at the sender side. The proposed playable bitrate model is very simple because it does not require the complex training procedure for obtaining model parameters, which is usually required in the conventional code rate decision method. It is shown by simulations that the proposed code rate decision scheme based on the playable bitrate model can efficiently determine the near-optimal code rate for JSCC in terms of high accuracy on the optimal code rate.