Adaptive Multi-Rate audio codec

About: Adaptive Multi-Rate audio codec is a research topic. Over the lifetime, 1467 publications have been published within this topic receiving 19736 citations. The topic is also known as: AMR & Adaptive Multi-Rate.

Phase Randomization-A new concept in Perceptual Audio Coding

Abstract: A novel technique of Phase Randomization (PR) for bit rate reduction in perceptual coding of high quality audio is presented. Instead of actual phase information, the decoder utilizes nevertheless?carefully?formulated `random' phase information for signal reconstruction with the help of a code sent by the encoder in every frame of data. The coding scheme is tested on the Digital Audio Broadcasting (DAB) Standard, for which broadcasters often desire an increase in the number of transmission channels for densely populated areas. The codec achieves the aim of providing good quality audio at a reduced bitrate assessed with the help of ITU-R BS. 1116 methodology for the subjective assessment of audio quality.

Multi-description Video Codec Based on Distributed Source Coding

Abstract: A new multi-description video coding scheme based on distributed source coding is proposed to solve the drift problem of the multi-description video codec under packet loss channels.Experimental results demonstrate that the proposed scheme can effectively avoid the drift problem by virtue of the robustness of distributed source coding.

An HDTV codec based on MPEG2 and its picture quality evaluation

Abstract: This paper describes the codec's specifications and results of subjective testing for decoded images at 12 Mbit/s to 36 Mbit/s. In this codec, the HDTV image is divided into four standard-TV-sized images, and multiple MPEG2 tools designed for standard TV are utilized. So, this codec could be made compact by using standard TV processing units for MPEG2, which will be widely available in the near future. Moreover, this HDTV codec has an architecture with which both HDTV processing and multiple standard TV processing is possible. As for the bit-rates, by introducing an image shaping function before MPEG2 compression, 12-18 Mbit/s transmission is possible with less picture degradation.

An efficient search algorithm for ISF vector quantization in AMR‐WB speech codec

Abstract: The adaptive multi-rate wideband (AMR-WB) speech codec with a sampling rate of 16 kHz is one of the speech codecs applied to 4G mobile communication systems as a way to remarkably improve the speech quality of a smartphone. However, a major drawback is that the vector quantization of the immittance spectral frequency (ISF) coefficients takes up the second largest of the total computational load of the AMR-WB encoder. In other words, the speech quality is improved at the cost of high battery power consumption. Accordingly, this letter presents a triangular inequality elimination algorithm equipped with a dynamic and an intersection mechanism, named DI-TIE, as a means to considerably improve the performance of ISF coefficient quantization in AMR-WB speech codec. Both mechanisms are designed in a way that recursively enhances the performance of TIE algorithm. This proposal is demonstrated by experimental results as a superior search algorithm relative to a conventional TIE and a multiple TIE (MTIE) approaches. With a full search algorithm as a benchmark for search load comparison, this work provides a search load reduction of more than 77%, a figure far beyond the 36% in the TIE and 49% in the MTIE approach. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.