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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.


Papers
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Proceedings ArticleDOI
14 May 2006
TL;DR: ITU-T test results showed that this coder passed all the requirements of the G729EV qualification phase.
Abstract: This paper describes a 8–32 kbit/s scalable speech and audio coder submitted as a candidate for the ITU-T G729-based Embedded Variable bitrate (G729EV) standardization. The coder is built upon a 3-stage coding structure consisting of: narrowband cascade CELP coding at 8 and 12 kbit/s, bandwidth extension based on wideband linear-predictive coding (WB-LPC) at 14 kbit/s, and MDCT coding in a WB-LPC weighted signal domain from 14 to 32 kbit/s. ITU-T test results showed that this coder passed all the requirements of the G729EV qualification phase.

26 citations

Patent
Yang Gao1
27 Aug 2001
TL;DR: In this article, a speech compression system capable of encoding a speech signal into a bitstream for subsequent decoding to generate synthesized speech is disclosed, which optimizes the bandwidth consumed by the bitstream by balancing the desired average bit rate with the perceptual quality of the reconstructed speech.
Abstract: A speech compression system capable of encoding a speech signal into a bitstream for subsequent decoding to generate synthesized speech is disclosed. The speech compression system optimizes the bandwidth consumed by the bitstream by balancing the desired average bit rate with the perceptual quality of the reconstructed speech. The speech compression system comprises a full-rate codec, a half-rate codec, a quarter-rate codec and an eighth-rate codec. The codecs are selectively activated based on a rate selection. In addition, the full and half-rate codec are selectively activated based on a type classification. Each codec is selectively activated to encode and decode the speech signals at different bit rates emphasizing different aspects of the speech signal to enhance overall quality of the synthesized speech. The overall quality of the system is strongly related to the excitation. In order to enhance the excitation, the system contains a fixed codebook comprising several subcodebooks. The invention reveals a way to apply a pitch enhancement efficiently and differently for different subcodebooks without using additional bits. The technique is particularly applicable to selectable mode vocoder (SMV) systems.

26 citations

Proceedings ArticleDOI
10 Dec 2002
TL;DR: An efficient codec architecture for context-based adaptive arithmetic coding is proposed, which exhibits low cost, low latency, and high throughput rate and can be programmed for supporting multiple standards such as JPEG, JPEG2000, JBIG, andJBIG2 standards.
Abstract: For next generation image compression standard, context-based arithmetic coding is adopted for improving the compression rate. An efficient and high throughput codec design is strongly required for handling high-resolution images. We propose an efficient codec architecture for context-based adaptive arithmetic coding, which exhibits low cost, low latency, and high throughput rate. In addition, it can be programmed for supporting multiple standards such as JPEG, JPEG2000, JBIG, and JBIG2 standards. It exploits three-pipeline stages architecture. Based on parallel leading zeros detection and bit-stuffing handling, symbols can be encoded and decoded within one cycle. Therefore, the throughput rate can be increased as high as the codec operating clock rate. For 0.35 /spl mu/ 1P4M CMOS technology, both the encoding and decoding rate can run up to 185 M symbol/sec. The AC codec only costs 12 K gate count and 860 /spl mu/m/spl times/860 /spl mu/m layout area. These performances can meet high-resolution real time application requirements.

26 citations

Proceedings ArticleDOI
23 May 1989
TL;DR: The authors propose a split-band coder structure, where both hands are coded with analysis-by-synthesis techniques in order to take advantage of their high coding gain, and show that the obtained speech quality is close to the original.
Abstract: The problem of coding speech at 7 kHz is considered. A possible application of these codecs could be the videophone, especially for hands-free telephone use. The authors propose a split-band coder structure, where both hands are coded with analysis-by-synthesis techniques in order to take advantage of their high coding gain. Two techniques are considered: multipulse coding and codebook-excited linear prediction. The structures of two possible codecs are described, and indications are given of the considerations that led to their design. Their main characteristic is the use, as far as possible, of excitation model parameters optimized within the analysis by synthesis loop, still maintaining a reasonable computational complexity. Subjective and objective results, obtained with high-quality speech, are reported. They show that the obtained speech quality is close to the original. >

26 citations

Proceedings ArticleDOI
08 Jun 1994
TL;DR: The paper summarizes the standardized PSI-CELP algorithm and the techniques used to improve speech quality, to reduce computational complexity, and to reduce memory requirements.
Abstract: A pitch synchronous innovation-CELP (PSI-CELP), proposed by NTT DoCoMo in 1993, is adopted as the Japanese half-rate PDC (personal digital cellular) speech codec standard. This algorithm is based on CELP (code excited linear prediction) with a pitch synchronized excitation source. It uses 3.45 kbit/s out of 5.6 kbit/s for speech coding and the remaining 2.15 kbit/s for error protection. The paper summarizes the standardized PSI-CELP algorithm. The techniques used to improve speech quality, to reduce computational complexity, and to reduce memory requirements are mentioned. A real time operating prototype based on this algorithm is also described. >

26 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202214
20201
20193
20183
201721