Robust video transmission using reversible watermarking techniques

This paper presents a novel error-resilient strategy which employs a reversible watermarking technique to protect the H.264/AVC video content. The proposed scheme adopts reversible watermarking to embed an error detection codeword within every Macro block (MB). The watermark is then extracted at the decoder and used to detect the corrupted MBs to be concealed. The proposed scheme further manages to recover the original video content after watermark extraction, thus providing no loss in video quality. The simulation results demonstrate that the proposed approach provides a substantial gain of up to 2.6 dB in Peak Signal-to-Noise Ratio (PSNR) relative to the standard with a minimal increase in complexity.peer-reviewe

A hybrid error control and artifact detection mechanism for robust decoding of H.264/AVC video sequences

This letter presents a hybrid error control and artifact detection (HECAD) mechanism which can be used to enhance the error resilient capabilities of the standard H.264/advanced video coding (AVC) codec. The proposed solution first exploits the residual source redundancy to recover the most likelihood H.264/AVC bitstream. If error recovery is unsuccessful, the residual corrupted slices are then passed through a pixel-level artifact detection mechanism to detect the visually impaired macroblocks to be concealed. The proposed HECAD algorithm achieves overall peak signal-to-noise ratio gains between 0.4 dB and 4.5 dB relative to the standard with no additional bandwidth requirement. The cost of this solution translates in a marginal increase in the complexity of the decoder. In addition, this method can be applied in conjunction with other error resilient strategies and scales well with different encoding configurations.peer-reviewe

Resilient video coding using difference expansion and histogram modification

Recent advances in multimedia technology have paved the way to the development of several applications, including digital TV broadcasting, mobile TV, mobile gaming and telemedicine. Nonetheless, real time multimedia services still provide challenges as reliable delivery of the content cannot be guaranteed. The video compression standards incorporate error resilient mechanisms to mitigate this effect. However, these methods assume a packet-loss scenario, where corrupted slices are dropped and concealed by the decoder. This paper presents the application of reversible watermarking techniques to facilitate the detection of corrupted macroblocks. A variable checksum is embedded within the coefficient levels and motion vectors, which is then used by the decoder to detect corrupted macroblocks which are concealed. The proposed method employs difference expansion to protect the level values while histogram modification was employed to protect the motion vectors. Unlike previous published work by the same author, this scheme does not need the transmission of side information to aid the recovery of the original level and motion vector values. Simulation results have indicated that significant gains in performance can be achieved over the H.264/AVC standard.peer-reviewe

Performance Evaluation of Centralized Reconfigurable Transmitting Power Scheme in Wireless Network-on-chip

Network-on-chip (NoC) is an on-chip communication network that allows parallel communication among all cores to improve inter-core performance. Wireless NoC (WiNoC) introduces long-range and high bandwidth radio frequency (RF) interconnects that can possibly reduce the multi-hop communication of the planar metal interconnects in conventional NoC platforms. In WiNoC, RF transceivers account for a significant power consumption, particularly its transmitter, out of its total communication energy. This paper evaluates the energy and latency performance of a closed loop power management mechanism which enables transmitting power reconfiguration in WiNoC based on number of erroneous received packets. The scheme achieves significant energy savings with limited performance degradation and insignificant impact on throughput

Robust decoder-based error control strategy for recovery of H.264/AVC video content

Real-time wireless conversational and broadcasting multimedia applications offer particular transmission challenges as reliable content delivery cannot be guaranteed. The undelivered and erroneous content causes significant degradation in quality of experience. The H.264/AVC standard includes several error resilient tools to mitigate this effect on video quality. However, the methods implemented by the standard are based on a packet-loss scenario, where corrupted slices are dropped and the lost information concealed. Partially damaged slices still contain valuable information that can be used to enhance the quality of the recovered video. This study presents a novel error recovery solution that relies on a joint source-channel decoder to recover only feasible slices. A major advantage of this decoder-based strategy is that it grants additional robustness while keeping the same transmission data rate. Simulation results show that the proposed approach manages to completely recover 30.79% of the corrupted slices. This provides frame-by-frame peak signal-to-noise ratio (PSNR) gains of up to 18.1%dB, a result which, to the knowledge of the authors, is superior to all other joint source-channel decoding methods found in literature. Furthermore, this error resilient strategy can be combined with other error resilient tools adopted by the standard to enhance their performance.peer-reviewe

Resilient Digital Video Transmission over Wireless Channels using Pixel-Level Artefact Detection Mechanisms

Recent advances in communications and video coding technology have brought multimedia communications into everyday life, where a variety of services and applications are being integrated within different devices such that multimedia content is provided everywhere and on any device. H.264/AVC provides a major advance on preceding video coding standards obtaining as much as twice the coding efficiency over these standards (Richardson I.E.G., 2003, Wiegand T. & Sullivan G.J., 2007). Furthermore, this new codec inserts video related information within network abstraction layer units (NALUs), which facilitates the transmission of H.264/AVC coded sequences over a variety of network environments (Stockhammer, T. & Hannuksela M.M., 2005) making it applicable for a broad range of applications such as TV broadcasting, mobile TV, video-on-demand, digital media storage, high definition TV, multimedia streaming and conversational applications. Real-time wireless conversational and broadcast applications are particularly challenging as, in general, reliable delivery cannot be guaranteed (Stockhammer, T. & Hannuksela M.M., 2005). The H.264/AVC standard specifies several error resilient strategies to minimise the effect of transmission errors on the perceptual quality of the reconstructed video sequences. However, these methods assume a packet-loss scenario where the receiver discards and conceals all the video information contained within a corrupted NALU packet. This implies that the error resilient methods adopted by the standard operate at a lower bound since not all the information contained within a corrupted NALU packet is un-utilizable (Stockhammer, T. et al., 2003).peer-reviewe

Robust error detection methods for H.264/AVC videos

The 3rd generation of mobile systems is mainly focused on enabling multimedia services such as video streaming, video call and conferencing. In order to achieve this, the Universal Mobile Telecommunications System (UMTS), is the standard that has been developed by the 3rd Generation Partnership ect (3GPP) in Europe, including the baseline profile of H.264/AVC in the specification. With the union of both technologies a great improvement on video transmission over mobile networks, and even modification of the user habits towards the use of the mobile phone is expected. Nevertheless, video transmission has always been related to wired networks and unfortunately the migration to wireless networks is not as easy as it seems. In real time applications the delay is a critical constraint. Usually, transmission protocols without delivery warranties, like the User Network Protocol (UDP) for IP based networks, are used. This works under the assumption that in real time applications dropped packets are preferable to delayed packets. Moreover, in UMTS the network needs to be treated in a different way, thus the wireless channel is a prone error channel due to its high time variance. Typically, when transmitting video, the receiver checks whether the information packet is corrupted (by means of a checksum) or if its temporal mark exceeds the specified delay. This approach is suboptimal, due to the fact that perhaps the video information is not damaged and could still be used. Instead, residual redundancy on the video stream can be used to locate the errors in the corrupted packet, increasing the granularity of the typical upper-layer checksum error detection. Based on this, the amount of information previous to the error detection can be decoded as usually. The aim of this thesis is to combine some of the more effective methods concretely, Syntax check, Watermarking and Checksum schemes have been reformulated, combined and simulated