Packet-loss concealment technology advances in EVS

Abstract

EVS, the newly standardized 3GPP Codec for Enhanced Voice Services (EVS) was developed for mobile services such as VoLTE, where error resilience is highly essential. The presented paper outlines all aspects of the advances brought during the EVS development on packet loss concealment, by presenting a high level description of all technical features present in the final standardized codec. Coupled with jitter buffer management, the EVS codec provides robustness against late or lost packets. The advantages of the new EVS codec over reference codecs are further discussed based on listening test results

Quality of Experience in Telemeetings and Videoconferencing: A Comprehensive Survey

“…For that reason, Figure 3 simplifies this by showing five major processing steps in the end device: Capture & Reproduction, Signal Enhancement, En-/De-Coding, Signal / Stream Mixing (in case of a peer-to-peer system as it requires clientside conferencing bridges), and Network Access. There is a vast amount of literature on the available technologies, ranging from electro-acoustic and electro-optic transducers (e.g., [69], [99]) over signal processing algorithms for signal enhancement and data compression (e.g., [36], [53]- [60], [63]- [68], [70]- [72]) to data error correction mechanisms for the packet streams (e.g., [100], [101]). Next to research work focusing on the technology, a number of publications discuss these technical aspects of telemeeting and telecommunication systems from a QoE perspective, e.g., [7], [51], [52], [61], [62], [95].…”

Application-Layer Redundancy for the EVS Codec

“…I [14], signal extrapolation based on linear-predictive coding (LPC) , classification, adaptive muting in ITU-T G.722 App. IV [15], or more advanced methods in EVS [16]. It can be noted that in voice over IP (VoIP) PLC may be integrated with JBM [17], and concealment and recovery may be implemented by JBM expand and merge operations at the reconstructed signal level.…”

Detecting Packet-Loss Concealment Using Formant Features and Decision Tree Learning

“…Since frame/packet loss or concealment is one of the main impairments in modern voice networks, it is necessary for such a problem identification model to detect these losses through audio analysis. Concealment algorithms of modern codecs try to synthesize a lost packet by repeating information from the previously received frames [7]. When the algorithm fails to synthesize a signal similar to the missed frame, it often results in robotic voice or artificial and annoying sounds.…”