Adaptive forward error correction for streaming stored mpeg-4 FGS video over wireless channel

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 coding technique has been desired for many years to fulfill the requirement of reliable transmission of video over heterogeneous networks. It allows for simple solutions in adaptation to network constraint and user capabilities by providing a full scalability including temporal, spatial and quality scalability. Various coding structures will dramatically affect the overall performance of the system. In this paper, we develop a new joint source and channel coding scheme for wireless broadcasting making use of H.264/SVC considering the various clients' statistics such as the accessing bandwidth and the error rate. First, an effective algorithm is carried out to distribute proper amount of source codes and channel codes to the base layer to guarantee that all the clients can receive the video with a minimum quality. Second, to deal with the burst packet loss, we propose to apply the unequal error protection (UEP) scheme on the enhancement layers using the interleaved packetization to make sure that all the lower layers can be decoded if an enhancement layer is correctly received. To maximize the system-defined utility function, fast algorithms are designed to dynamically allocate the source coding rate and the channel coding rate for the scalable bit-stream given the clients' distribution. Experiments are conducted to verify the performance of the proposed algorithm against the other two schemes, where equal error protection (EEP) and UEP schemes with different coding structures are employed. The results demonstrate the superiority of the proposed scheme and the improvement is up to 2 dB.

We present a dynamic unequal error protection (UEP) framework for the embedded image bit streams over noisy channels. A general source model for M-rate UEP schemes is derived and an optimization algorithm for 2-rate dynamic UEP schemes is developed. To facilitate the design and implementation of UEP schemes, we also derived a necessary condition and an upper bound for UEP gains. Simulation results demonstrate about 0.3 dB improvements over equal error protection (EEP) schemes at the price of negligible overheads while the progressiveness of the original bit streams is still kept.

The MPEG-4 video compression standard incorporates several techniques to create error-resilient coded video. These techniques are effective against a certain level of errors. However, wireless channels often have very high error rates; thus channel coding is needed to reduce the number of errors in the compressed bitstream that is sent to the MPEG-4 video decoder. The structure of an MPEG-4 compressed bitstream lends itself to using unequal error protection to ensure fewer errors in the important portions of the bitstream. This paper discuses how unequal error protection can be used with the MPEG-4 error resilience tools and describes several experiments using both unequal and equal error protection on video sent through a simulated GSM channel. The results of these experiments show that when the bit error rate is high, unequal error protection can improve reconstructed video quality by as much as 1 dB compared with equal error protection.

In view of increasing use of video transmission over wireless channels, a lot of research efforts have been made to trade-off the error resiliency and transmission bandwidth requirements. This in turn has led to development of various unequal error protection (UEP) schemes. In this paper, the performance of optimized 2-layered and 3-layered UEP schemes using hierarchical 64 QAM (64-HQAM) for wavelet-transformed images coded with set partitioning in hierarchical trees (SPIHT) algorithm and transmitted over additive white Gaussian noise (AWGN) channel is investigated. A look-up table (LUT) based approach to select the optimal values of modulation parameters of 64-HQAM for different channel conditions is suggested so as to reduce the computational complexity. Simulation results show that 3-layered optimized 64-HQAM-based UEP outperforms corresponding non-optimized UEP. Also, 3-layered optimized UEP scheme using 64-HQAM performs slightly better as compared to optimized 2-layered UEP scheme using 64-HQAM.

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.

In this paper we propose an image coding scheme based on Block Turbo Codes (BTC) for protecting SPIHT coded images transmitted over wireless channels. An Unequal Error Protection (UEP) scheme using different product codes is also presented. The optimization of the UEP scheme under a transmission budget constraint is investigated. Performance of the proposed system are first evaluated over Gilbert-Elliott (GE) channels. They are then compared to the well-known system of Sherwood and Zeger, through numerical simulations over a single path Rayleigh fading channel. Then, we present an optimized mobile image transmission framework involving a multiuser asynchronous DS-CDMA transmission system over Rayleigh multipath channels. Simulation results for the 512x512 Lena image, transmitted over the ITU Vehicular A channel, show that a significant gain in PSNR is obtained by using the SIC/RAKE multiuser detector in comparison with a conventional detection by the RAKE receiver. Furthermore, performance are also improved when introducing the UEP scheme.

The utilization of forward error correction (FEC) schemes for stereo video streaming is investigated. Stereo video is categorized in 3 layers and each layer is protected with different protection ratios for efficient streaming. Systematic Reed-Solomon (RS) and Luby Transform (LT) codes are utilized as the error protection schemes. Detailed simulations are performed in order to observe the optimum unequal error protection (UEP) strategies for the defined video layers. Moreover, as a result of these simulations the performance comparison of RS and LT codes for video streaming is provided.

Online video transmissions over wireless networks are rising in popularity and have already become part of our daily life. In the meantime, it is necessary to address a number of challenges ranging from the scarce resources, time-varying, and high error rates, to the fluctuating bandwidth, unveiling the need for an adaptive mechanism to ensure a good video transmission. Adaptive Forward Error Correction (FEC) techniques with Quality of Experience (QoE) assurance are appropriate to deliver QoE-aware video data to wireless users in dynamic and high error rates networks. This paper proposes an adaptive Video-aware FEC and Fuzzy Logic-based mechanism to shield realtime video transmissions against packet loss in wireless networks, improving both user experience and the usage of resources. The benefits and drawbacks of the proposed mechanism compared with exiting work are demonstrated through simulations and assessed with QoE metrics.

On account of the wireless channel interference, transmission data tends to be erroneously decoded at the receiver. Even received with errors in some extent, the video can still be successfully recovered because of its error resilience, e.g. videos encoded with H.264/AVC. According to recent research, when a bit sequence is modulated to constellation symbols, different bit positions of symbols may have different probabilities of error occurrence. To exploit whether differential protection could be provided to different data bits of a video streaming based on this feature, our experiment implements this UEP (unequal error protection) scheme together with the data partitioning mechanism in H.264/AVC video encoding standards. The experiment results show the UEP scheme gains 5 dB of PSNR improvement in average than the EEP (equal error protection) scheme. While once massive errors occur, packets must be discarded and retransmissions are required, so additional resource consumption is unavoidable. To solve this problem, unequal loss protection (ULP) for H.264 bit stream is proposed in this paper. And we find a fact through experiments that when bandwidth resource is limited, insignificant partial data of H.264 bit stream could be discarded selectively without arousing obvious video quality degradation. Our simulation shows that when the unimportant network abstraction layer units (NALU) of H.264 bit stream are discarded, approximately 20 % of bandwidth resource is saved.

Efficient utilization of bandwidth is key to providing mobile multimedia services such as wireless imaging. As such, efficient allocation of the available parity budget for error protection of the associated codestreams is essential for ensuring quality of service. Computing the optimal parity allocation to the codestream packets may not be possible in real-time due to the huge number of ways the parity can be assigned to the codestream packets. This is particularly true for systems having limited resources, such as mobile handheld devices. As a result, it is important to provide an error-protection scheme that gives good error-protection performance while imposing low computational and memory demands on the system. We therefore analyze how different parameters such as signal-to-noise ratio and source distortion-rate function affect the optimal unequal error protection (UEP) scheme for embedded codestreams. We also propose to approximate the optimal UEP using suitable mathematical models in order to reduce the complexity that otherwise would occur with computing the optimal UEP. We investigate several models for their fitness in approximating the optimal UEP using different performance metrics. The simulation results show that most of these models provide an excellent trade-off between performance and complexity.

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.

Asymmetric Digital Subscriber Line (ADSL) is a broadband communications technology which is widely used for transmitting high bandwidth data such as audio and video over the internet. However, ensuring a good Quality of Service (QoS) in the transmission of such data over ADSL is challenging due to channel impairments such as noise and crosstalk. Moreover, given that the total monthly fixed data traffic is increasing at a phenomenal rate, (QoS) management is becoming a crucial issue. This paper proposes an enhanced transmission scheme for audio over ADSL. The proposed scheme exploits the unequal importance of the subbands generated by an MP1 codec to offer varying protection to them during ADSL transmission. This is achieved by multiplexing the bit streams from the subbands before Discrete Multi-tone Modulation (DMT) so that bit streams corresponding to more important subbands are offered higher protection than the least important ones. Additionally, a sophisticated retransmission protocol is proposed which allows frames from more important subbands to benefit from a greater number of retransmissions than least important ones. The retransmission protocol uses eight different Negative Acknowledgement (NACK) packet types which allow adaptive multiplexing of frames at the transmitter. The proposed Unequal Error Protection (UEP) scheme provides an average gain of over 28 dB in Segmented Signal to Noise Ratio (SSNR) over a conventional Equal Error Protection (EEP) one but incurs a negligible loss in throughput.

Give a limited bandwidth, unequal error protection (UEP) via channel coding with different code rates for different important regions of bitstream may yield much less error contamination than equal error protection (EEP). We propose an optimal code rate allocation scheme that minimizes error contamination after channel and source decoding. We use JPEG2000 for source coding and turbo product code (TPC) for channel coding as an example to demonstrate this technique with ultraspectral sounder data. The statistics of erroneous pixels after TPC and JPEG2000 decoding are used to determine the optimal channel code rates for each wavelet resolution. The proposed UEP scheme significantly reduces error contamination when compared to its EEP counterpart. The optimal code rate allocation needs to be determined only once, given any predefined set of available channel codes, desired code rate, and noise level.

Unmanned aerial vehicles (UAV) are rising in popularity together with video applications for both military and civilian use. Because of that, it is necessary to address a set of challenges related to the device movement, scarce resources as well as high error rates, making evident the need for an adaptive mechanism to strengthen video transmissions. Adaptive Forward Error Correction (FEC) techniques are known to be suitable to enhance the Quality of Experience (QoE) of video transmitted over error-prone wireless networks with high mobility. This book chapter proposes an adaptive video-aware FEC mechanism that uses motion vectors details to improve real-time UAV video transmissions, providing both higher user experience and better usage of resources. The benefits and drawbacks of the proposed mechanism along with the related work are analysed and put up for test through simulations and evaluated using QoE metrics.