NTT Research and Development 2009 Review of Activities

Overview

LDGM code^* is an error-correction technology that can continuously reproduce video contents. In general, LDGM code is suitable for transmission of huge-capacity contents like that used in 4K cinemas. However, the LDGM code had been improved by combining sub-packet divisions and interleaving. As a result, it is possible to correct errors for several devices involved in multi-cast transmission. Moreover, by adding parity information to the original source without changing the original source, the LDGM code allows video viewing even if the user environment does not incorporate error-correction modules.

Features

• Applications from low-bit-rate video for mobile phones to high-bit-rate movies for theater
• Software implementation with low complexity is easy
• Compatibility is assured by adding redundant information without altering the original data
• Partial decoding can be done according to layered data
• Improved coding efficiency by combining sub-packet divisions and interleaving

Application scenarios

• Large-scale multi-cast video streaming service
• Huge-data-transmission service
• Video streaming service for pocket devices with limited computing resources
• Improved robustness of existing multi-cast delivery services
• Live broadcasting for high-quality premium contents in theaters

• * LDGM (Low Density Generator Matrix) code: A code based on very sparse matrix offers linear-time encoding and decoding.