Topic
Enhanced Variable Rate Codec
About: Enhanced Variable Rate Codec is a research topic. Over the lifetime, 357 publications have been published within this topic receiving 4842 citations. The topic is also known as: EVRC.
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17 Jun 2013TL;DR: Simulation results measuring the mean opinion score of voice quality show that superior voice quality can be achieved with this method over using standalone codecs while maintaining excellent quality of service for data traffic as well.
Abstract: As converged services are becoming the standard for corporate networks, concerns have been arising on the best way to ensure efficient use of expensive WAN bandwidth. Achieving excellent quality of multimedia and voice communication requires the allocation of large bandwidth for these services. In most cases, lossy compression codecs are used to reduce bandwidth requirements resulting in lower quality of service. The codec selection is maintained even during low bandwidth utilization. In this paper, we present a codec interface that combines high-fidelity high-bitrate and low-fidelity low-bitrate codecs. Audio packets from the low-bitrate codec are transmitted on the highest priority class of service of differentiated services networks. This ensures that these packets always arrive at destination. Audio packets from the high-bitrate codec are transmitted on the lowest priority class of service. At low bandwidth utilization, the high-fidelity high-bitrate packets will be used and during congestions, these packets would be dropped. This ensures achieving the best possible voice quality during varying network loads. Simulation results measuring the mean opinion score of voice quality show that superior voice quality can be achieved with this method over using standalone codecs while maintaining excellent quality of service for data traffic as well.
2 citations
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13 Oct 2004
TL;DR: In this paper, a method and system for extracting/combining/transmitting audio data by using a microphone of a mobile terminal are provided to allow a user to combine video data and a user's voice, and transmit the corresponding multimedia data to a receiver.
Abstract: PURPOSE: A method and system for extracting/combining/transmitting audio data by using a microphone of a mobile terminal are provided to allow a user to combine video data and a user's voice, and transmit the corresponding multimedia data to a receiver. CONSTITUTION: When a key input for photographing and recording is inputted from a key input unit(S310), a CPU(Central Processing Unit) transmits a record function for setting a sound media as a recording audio in order to record audio data to an EVRC(Enhanced Variable Rate Coding) vocoder(S320). When a key input for an audio volume is inputted from the key input unit(S330), the CPU transfers a volume setting function for setting a volume of EVRC audio data to be extracted and a volume set value designated by the key input unit to the EVRC vocoder(S340). When the EVRC audio data is received from the EVRC vocoder(S350), the CPU stores the EVRC audio data in a data storing unit(S360).
2 citations
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12 Sep 2001TL;DR: The CODEC will be shown to have the ability to be optimized for a specific application as well as to be re-targeted to different fabrication lines.
Abstract: While the conventional concept of a signal coder-decoder (CODEC) is of a homogeneous device, such that the output decoding is simply an inverse of the input decoding, the heterogeneous CODEC developed in this paper decouples the input and output decoding; this variation generalizes the system. A control CODEC is an application of a heterogeneous CODEC, which replaces a traditional discrete analog control loop. The CODEC will be shown to have the ability to be optimized for a specific application as well as to be re-targeted to different fabrication lines. Because of the environmental demands on space-borne devices several stable radiation-hardened (rad-hard), silicon-on-insulator (SOI), BiCMOS processes were used. The MIT Lincoln Labs AST Fully Depleted SOI (FDSOI) deep-submicron process was also used as an example of re-targeting. Our technology independent methodology implements a deliberate mixed-signal design decomposition, which enhances analog and mixed-signal block reuse.
2 citations
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TL;DR: In this paper, the authors describe the selection process, results of the selection, and subsequent tests to characterize the performance of the selected wideband speech codec, VMR-WB.
Abstract: The voice services sub-working group of 3GPP2 conducted a standardization effort to select and characterize the first wideband speech codec for cdma2000reg. This article describes the selection process, the results of the selection process, and the subsequent tests to characterize the performance of the selected wideband speech codec, VMR-WB
2 citations