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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01 Jan 1992
TL;DR: The paper describes the structure of the CELP codec, the assessment of the bit error sensitivity, the choice of suitable channel codes, and the real-time hardware concept.
Abstract: A digital speech codec for mobile satellite communication has been developed. It includes both source and channel coding on two digital signal processors. A CELP (code-excited linear predictive) speech coder has been combined with a channel coder using RCPC (rate compatible punctured convolutional) codes providing an unequal error protection. The paper describes the structure of the CELP codec, the assessment of the bit error sensitivity, the choice of suitable channel codes, and the real-time hardware concept.
1 citations
01 Oct 2009
TL;DR: An adaptive paired-comparison subjective testing algorithm is used to efficiently adapt BER values for the EFR and EHR codecs to quickly locate the BERvalues where listeners found the speech quality to be the same as the reference.
Abstract: When bit errors are introduced between a speech encoder and a speech decoder, the quality of the received speech is reduced. The specific relationship between speech quality and bit error rate (BER) can be different for each speech coding and channel coding scheme.
This report describes a subjective experiment concerning the relationships between BER and perceived speech quality for the TIA Project 25 Full Rate (FR), Enhanced Full Rate (EFR), and Enhanced Half Rate (EHR) speech codecs. Using the FR codec with 2 % random bit errors as a reference, we sought to characterize the BER values for which the EFR (or EHR) codec produces speech quality that is equivalent to the reference. We used an adaptive paired-comparison subjective testing algorithm to efficiently adapt BER values for the EFR and EHR codecs to quickly locate the BER values where listeners found the speech quality to be the same as the reference.
The results from sixteen listeners reveal ranges of BER values that were judged to produce speech quality equivalent to the reference. When these ranges are reduced to central values, those values indicate that on average, the EFR and EHR codecs are more robust to bit errors than the FR codec. We provide a set of additional results from a popular objective speech quality estimator for comparison purposes.
Patent•
28 Oct 2005
TL;DR: In this article, the authors propose a method of extracting a subset of speech units from a larger set of speech unit for use by a speech synthesizer in synthesizing speech, wherein the speech units are stored in a compressed encoded representation that was generated by a codec.
Abstract: A method of extracting a subset of speech units from a larger set of speech units for use by a speech synthesizer in synthesizing speech, wherein the speech units are stored in a compressed encoded representation that was generated by a codec, the method comprising: selecting members of the subset of speech units based on an overall cost associated with using the speech synthesizer to synthesize a test set of speech, wherein the overall cost includes at least one error introduced by using the codec to decode the stored representations of the speech units; and storing the selected subset of speech units on a speech-enabled device.
01 Jan 2013
TL;DR: A reliability-based selective encoding scheme based on the pixel-domain Wyner-Ziv residual (PDWZR) video codec that performs better than the DISCOVER scheme as well as the H.264 intra-mode coding scheme.
Abstract: In order to overcome the performance limitation of the conventional DVC schemes, this paper presents a reliability-based selective encoding scheme based on the pixel-domain Wyner-Ziv residual (PDWZR) video codec. At the decoder, the unreliability of the previously reconstructed WZ frame is investigated and then, by exploiting temporal correlations, the reliability of side information is estimated in a block unit. Then, the location information of the unreliable blocks is provided to the encoder side and thus it enables the encoder to selectively encode the frame difference signal in pixel-domain Wyner-Ziv residual encoder. Experimental results show that the proposed scheme performs better than the DISCOVER scheme as well as the H.264 intra-mode coding scheme.
30 Oct 2015
TL;DR: In HiJack platform to complete the 2 FSK codec and Manchester codec driver development and driver development based on the android operating system as well as to test these two communication encoding data communication performance between platforms and intelligent terminals.
Abstract: Keywords.intelligent terminal,communication based on audio technology,Manchster-coded, 2FSK Abstract.According to the characteristics of our intelligent terminal audio port communication technology, Improving the communication done in-depth analysis and research on the coding efficiency.In HiJack platform to complete the 2 FSK codec and Manchester codec driver development and driver development based on the android operating system as well.And we tested these two communication encoding data communication performance between platforms and intelligent terminals.