Block Recovery Rate-Based Unequal Error Protection for Three-Screen TV

This paper describes the design and implementation of a multimedia home gateway for threescreen television (3STV) service. The proposed in-home wireless network uses scalable video coding (SVC) and unequal error protection with Raptor forward error correction (FEC) for maximizing the quality of experience (QoE) over the variable-bandwidth, error-prone wireless network. The gateway incorporates (a) dynamic SVC layerswitching, which enables the server to perform selecting appropriate layers from SVC bitstreams, (b) adaptive Raptor FEC, which controls the overhead of Raptor FEC according to packet loss rate (PLR), (c) an efficient combination of (a) and (b), and (d) slice group-based selective streaming in the overall gateway architecture. The paper explains the home gateway architecture as well as experiments for performance evaluation as compared to that of traditional SVC streaming. In the experiments conducted, gains in video quality vary from 2 to 5dB in peak signal-to-noise ratio (PSNR), with corresponding subjective improvements. Overall reductions of bit rate at the input to the home gateway vary from 28% to 36% <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> .

This paper investigates how Scalable Video Coding (SVC) can benefit from different Forward Error Correction (FEC) and transmission schemes in mobile broadcast systems. Simulation are performed in DVB-H (Digital Video Broadcasting - Handheld) systems. In DVB-H, a differentiation in robustness for the different SVC layers can be achieved at the link layer using intra-burst MPE-FEC (multi-Protocol Encapsulation FEC). The paper evaluates the gain that can be achieved with the MPE-FEC using equal (EEP) and unequal error protection (UEP), and the performance improvements of an SVC layer-aware FEC (LA-FEC) approach that can be implemented in DVB-H either at the link layer with MPE-iFEC (inter-burst MPE-FEC) or at the application layer with AL-FEC. LA-FEC improves the SVC base layer robustness generating parity information across existing dependencies within the SVC video coding structure. Laboratory measurement results using a TU6 channel model show that the performance of an SVC service in DVB-H can be significantly increased by a proper link layer FEC scheme. It is shown that using SVC in combination with LA-FEC and a proper transmission scheduling does not only give a better performance in terms of PSNR and amount of video outages compared to a single layer service at the same service bit rate, but also gives an additional lower quality layer which can be used for applications like conditional access.

Video communication requires sufficient resources to obtain the desired image quality. Availability of bandwidth and screen resolution from different devices on the client end, as well as compression techniques used for transmission also significantly influence to the video quality. Even though the H.264/AVC video compression standard and its scalable extension is known as Scalable Video Coding (SVC) was introduced and successfully addressed the challenge, some weaknesses persist especially for high-resolution video transmissions. The size of the bitstream generated by the SVC standard for ultra-high resolution video compression can only be met if transmitted on a network with a large bandwidth. The Scalable High-Efficiency Video Coding (SHVC) were introduced to overcome problems in the SVC standards. The new video compression standard is proven to reduce bandwidth requirements by up to 46.41 % compared to the SVC standards for the same video quality. This study introduces the performance analysis of SHVC standard video transmission as compared to SVC standard. Both compression standards are transmitted and emulated through network emulator called Mininet-Wifi to get the real transmission picture. The client-server video transmission scheme with different bandwidth and various client position are set in the experiment scenario. It is found that transmission time, packet loss, and video reconstruction quality on scalable video transmission with SHVC standard is better than scalable video transmissions with SVC standard.

This paper introduces Adaptive and Reliable Forward Error Correction (AR_FEC), a novel mechanism that is designed to ensure reliable and efficient real-time video delivery for Unmanned Aerial Vehicles (UAVs). UAVs communicate using wireless channels that are inherently unreliable. AR_FEC is an application-layer solution that is inspired by edge computing. It incorporates several elements, specifically, adaptive Forward Error Correction (FEC), dynamic video quality, and Unequal Error Protection (UEP). AR_FEC dynamically adjusts the number of redundancy frames per video Group of Picture (GoP) based on packet loss rate, recent average round-trip times, and cross-layer information such as bandwidth usage and network traffic load. Moreover, AR_FEC reacts to congestion via a dynamic video quality algorithm. By adaptively determining suitable redundancy for the video I-frames and adjusting video quality, significant improvements are achieved. Comprehensive simulations demonstrate that the proposed AR_FEC protocol offers excellent performance for the number of delivered frames, latency, throughput, and delivery of frames, within the delay constraints for real-time multimedia streaming from UAVs.

Scalable video multicast using inter-layered superposition and network-coded cooperation over MIMO relay systems

With the rapid development of multimedia technology, video transmission over error prone channels is becoming possible. Lossy video coding together with channel errors result in more degradation in quality of the video. Unequal Error Protection (UEP) can be employed for solving this issue. Using UEP with scalable video coding (SVC) improves the quality of the transmitted video. The efficiency of this combination can be further enhanced by carefully considering the importance of each protected element. In this paper, we propose an efficient UEP scheme to protect scalable video, coded with the scalable extension of H.264/AVC, over networks with packet loss. Genetic algorithm (GA) is exploited to achieve the optimal rate allocation for each layer. Experimental results show a significant improvement of 1.15dB in average, in comparison with conventional methods.KeywordsUnequal error protection (UEP)scalable video coding (SVC)H.264/AVCGenetic Algorithm (GA)Reed Solomon coding

The unequal error protection (UEP) has shown promising results for transmitting video over error-prone wireless channels. In this paper, we investigate the cross-layer design of forward error correction (FEC) schemes by using the UEP Raptor codes at the application layer (AL) and UEP rate compatible punctured convolutional (RCPC) codes at physical layer (PHY) for prioritized video packets. The video packets are prioritized based on their contribution to the received video quality. A genetic algorithm (GA)-based optimization algorithm is proposed to find the optimal parameters for both Raptor and RCPC codes, to minimize the video distortion and maximize the peak signal-to-noise-ratio for the given video bit rates and channel constraints (i.e., SNR and available bandwidth). We evaluate the performance of four combinations of the UEP schemes for H.264/AVC encoded video sequences over the AWGN and Rayleigh fading channels and show the superiority of the optimized cross-layer UEP FEC scheme. For Rayleigh fading channel, the proposed cross-layer optimization uses two different time-scales at AL and PHY which allows PHY to adapt faster to the changing channel quality.

Virtual reality (VR) and augmented reality (AR) applications with interactions are usually delay-sensitive. Fast delivery of three-dimensional (3-D) models in VR/AR over wireless networks has been a crucial task due to limited bandwidth and packet error. In this paper we propose an application layer content-aware joint source-channel coding scheme based on forward error correction (FEC). A 3D model is progressively encoded to a base mesh and several refinement layers consisting of connectivity and geometric data. A new design of LT code with a special coding graph has been proposed to provide unequal error protection (UEP) to these two kinds of data. Then a statistical measure is used to optimize the rate allocation for each refinement layer, which is scalable to both network bandwidth and packet loss rate (PLR). Experimental results show that the proposed streaming scheme can achieve the objectives of low transmission delay and small distortion under serious loss.

In heterogeneous network environments, it is mandatory to measure the grade of the video quality in order to guarantee the optimal quality of the video streaming service. Quality of Service (QoS) has become a key issue for service acceptability and user satisfaction. Although there have been many recent works regarding video quality, most of them have been limited to measuring quality within temporal and Signal-to-Noise Ratio (SNR) scalability. H.264/AVC Scalable Video Coding (SVC) has emerged and has been developed to support full scalability. This includes spatial, temporal, and SNR scalability, each of which shows different visual effects. The aim of this paper is to define and develop a novel video quality metric allowing full scalability. It focuses on the effect of frame rate, SNR, the change of spatial resolution, and motion characteristics using subjective quality assessment. Experimental results show the proposed quality metric has a high correlation to subjective quality and that it is useful in determining the video quality of SVC.

Nowadays, it is still a challenge to offer high quality and reliable real-time video services over wireless network. In this paper, we studies a new practical scalable video coding (SVC) multicast scheme based on unequal error protection (UEP) framework with priority transmission. Firstly, we propose a 3D layer-based priority ordering method to determine the importance of scalable video bit stream. Then we present an adaptive packetization algorithm to allocate the source and channel code bit rate for ordered layers and guarantee the layers with highest importance could be recovered first. Simulation results show that the proposed scheme offer better performance than existing methods in preserving video quality for different kinds of sequences under various channel conditions.

Using the scalable video coding (SVC) extension of the H.264/AVC video coding standard, encoding a video sequence yields a quality, resolution, and frame-rate scalable bit-stream. This means that a version of the video sequence with a lower resolution, quality and/or frame rate can be obtained by extracting selected parts of the scalable bit-stream, without the need for re-encoding. In this way, easy adaptation of the video material to the end-users' device (computational power and display resolution) and channel characteristics is possible. In this paper, the use of unequal error protection (UEP) for error-resilient transmission of H.264/SVC-encoded video sequences is studied. By using unequal error protection, graceful degradation of the video quality is achieved when the targeted packet loss probability is exceeded. In contrast, using equal error protection (EEP), an immediate and dramatic drop in quality is observed under these conditions.

In real-time video streaming, data packets are transported over the network from a transmitter to a receiver. The quality of the received video fluctuates as the network conditions change, and it can degrade substantially when there is considerable packet loss. Forward error correction (FEC) techniques can be used to recover lost packets by incorporating redundant data. Conventional FEC schemes do not work well when scalable video coding (SVC) is adopted. In this paper, we propose a novel FEC scheme that overcomes the drawbacks of these schemes by considering the reference picture structure of SVC and weighting the reference pictures more when FEC redundancy is applied. The experimental results show that the proposed FEC scheme outperforms conventional FEC schemes.

An FEC scheme combined with weighted scheduling to reduce multicast packet loss in IPTV over PON

현재의 인터넷은 가변적인 대역폭과 패킷손실 그리고 지연으로 인하여 대화식 응용의 QoS 보장이 어렵다. 특히 최근에 정보의 기반구조로 중요성이 강조되고 있는 VOIP는 패킷손실률과 종점간지연이 클 때 통화품질이 크게 떨어지므로 네트웍 수준에서나 응용 수준에서 에러제어 기법이 요구된다. 인터넷 전화와 같은 대화식 응용을 위한 응용 수준의 에러 제어 기법으로 FEC(Forward Error Correction)가 가장 많이 사용되고 있는데, 이 기법은 주정보와 더불어 부가정보를 전송함으로서 패킷손실을 복구하는 방법으로 네트웍의 상태에 따라 적응적으로 부가정보의 양을 조절한다. 그러나 기존의 알고리즘들은 패킷손실률만을 고려하여 부가정보를 조절하였으며 부가 정보를 증가시킬 때 수반되는 종점간지연을 간과함으로써 통화품질을 떨어뜨리는 단점이 있다. 본 논문에서는 패킷손실률뿐만 아니라 종점간지연을 고려하는 FEC기반 에러제어 기법인 SCCRP (Selecting a Codec Combination using Reward and Penalty)를 제안한다. 실험 결과, SCCRP는 다른 알고리즘들에 비해 복구 후 패킷손실률은 물론 복구 후 종점간지연을 낮게 유지하였다. In the current Internet, the QoS of interactive applications is hardly guaranteed because of variable bandwidth, packet loss and delay. Moreover, VoIP which is becoming an important part of the information infra-structure in these days, is susceptible to network packet loss and end-to-end delay. Therefore, it needs error control mechanisms in network level or application level. The FEC-based error control mechanisms are used for interactive audio application such as VoIP. The FEC sends a main information along with redundant information to recover the lost packets and adjusts redundant information depending on network conditions to reduce the bandwidth overhead. However, because most of the error control mechanisms do not consider end-to-end delay but packet loss rate, their performances are poor. In this paper, we propose a new error control algorithm, SCCRP, considering packet loss rate as well as end-to-end delay. Through experiments, we confirm that the SCCRP has a lower packet loss rate and a lower end-to-end delay after reconstruction.

Despite the emergence of voice over IP and videoconferencing services, recent studies have shown that the Internet still may not provide acceptable quality for interactive streaming applications. Among the major parameters that affect quality of service are packet loss rates and loss burst sizes. To mitigate the negative impact of losses, forward error correction (FEC) techniques can be employed. These work by adding extra information to the data stream. So, while FEC can potentially reduce the perceived effects of packet losses, it increases bandwidth requirements which in turn may increase the loss rate. Therefore, it is important to choose, in real time, the proper FEC scheme to provide the best performance to the application. We evaluate the performance of parity-based FEC schemes using an analytical loss model. Then, we develop an adaptive mechanism for FEC selection using a predictive model. We present the results of simulation experiments using real Internet measurements.