Topic
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.
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Papers
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01 Dec 2015TL;DR: An adaptive selection scheme is devised in which the window shape selected depends on the periodicity of the signal, which has proven to be effective for LP analysis and to enhance the coding efficiency in both time and frequency domains in general.
Abstract: Lag windowing has long been used for the autocorrelation method of linear predictive (LP) analysis to prevent possible instability of the synthesis filter with the obtained coefficients. We have investigated the lag-window shape in terms of the trade-offs between stability and the coding efficiency. On the basis of these investigations, we have devised an adaptive selection scheme in which the window shape selected depends on the periodicity of the signal. This scheme has proven to be effective for LP analysis to enhance the coding efficiency in both time and frequency domains in general. This scheme has thus been included in the speech and audio coding schemes of the newly established 3GPP EVS codec standard.
1 citations
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22 Jun 2006TL;DR: This paper presents a reconfigurable architecture for the ACS block that enhances in area reduction of ACS block by almost 20% and gives significant reduction in time consumption.
Abstract: Today's modern mobile communications require minimum bandwidth, minimum loss, delay and better transmission of speech. This paved a way for the development of speech codec with low bit rates among which CELP codec inherit the merits of both waveform and source codec. The most time consuming and computational intensive process in modern speech codec is algebraic code book search (ACS). The 30% of process is done by this ACS in speech codec. This paper presents a reconfigurable architecture for the ACS block. This proposed architecture enhances in area reduction of ACS block by almost 20%. Further it gives significant reduction in time consumption
1 citations
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12 Oct 1998
TL;DR: This paper presents a new variable bit-rate CELP speech coder based on fuzzy phonetic classification and CS-ACELP structure that performs better than that of the GSM full-rate codec and similar to the latest ITU-T standard for speech coding at 8 kbit/s, both in the discontinuous transmission mode.
Abstract: This paper presents a new variable bit-rate CELP speech coder based on fuzzy phonetic classification and CS-ACELP structure The codec exploits new robust algorithms of multilevel phonetic classification and efficient activity/inactivity speech coding models It uses 8 operating modes ranging from 0 to 8 kbit/s with an average bit rate of 4 kbit/s and an algorithmic delay of 15 ms Subjective listening tests, performed in several acoustic noise conditions, demonstrate that performance is better than that of the GSM full-rate codec at 13 kbit/s and similar to that of the latest ITU-T standard for speech coding at 8 kbit/s, both in the discontinuous transmission mode
1 citations
15 Dec 2009
TL;DR: This document specifies a Real-time Transport Protocol (RTP) payload format to be used for the low complexity subband codec (SBC), which is the mandatory audio codec of the Advanced Audio Distribution Profile (A2DP) Specification written by the Bluetooth(r) Special Interest Group (SIG).
Abstract: This document specifies a Real-time Transport Protocol (RTP) payload
format to be used for the low complexity subband codec (SBC), which is
the mandatory audio codec of the Advanced Audio Distribution Profile
(A2DP) Specification written by the Bluetooth(r) Special Interest
Group (SIG). The payload format is designed to be able to interoperate
with existing Bluetooth A2DP devices, to provide high streaming audio
quality, interactive audio transmission over the internet, and ultra-
low delay coding for jam sessions on the internet. This document
contains also a media type registration which specifies the use of the
RTP payload format.
1 citations