Error Concealment for Frame Losses in MDC

Recent Patents on Signal Processing, 2011

Router buffer overflow and random bit errors have always been a problem in the Internet. The growth in multimedia applications in mobile extensions of the Internet has increased the threat from error bursts, random errors, and packet erasures that are a manifestation of wireless channels. Source-coded error resilience has come to prominence in the H.264/AVC codec standard, and this paper reviews such innovations surrounding this codec. Some innovations are new variants of an existing technique such as datapartitioning and some are entirely new such as the powerful dispersed-mode flexible macroblock ordering. Other techniques, such as reversible variable length coding, were not be transferred to H.264 from earlier codecs and, hence, innovations are proposed to still provide robust entropy coding. Other variants such as adaptive intra-refresh are still being experimented with. When error resilience or other protection methods fail to present an adequate video frame then error concealment can be brought to bear. This paper reviews error concealment which is important to commercial companies as they are able to distinguish their codec from others. The paper considers spatial, temporal and hybrid error concealment methods. Though this paper contains over one hundred references it can only provide a slice through this rich field.

The audiovisual and multimedia services are seen as important sources of data transmission within mobile networks these days. One of the limitations within the mobile networks is the low transmission bit rate which demands the reduction of the used video resolution and a high efficient video compression technique. Standard H.264/AVC, which is explained in this paper, is the newest codec of video compression, which provides a distinct improvement of quality in comparison with the previous video standards. Video stream transmission via wireless area results in data lost. It causes the emergence of the visual artefacts, and so the distinct fall of the picture quality. Since video stream transmission in real time is limited by transmission channel delay, it is not possible to transmit all faulty or lost packets. It is therefore inevitable to conceal these defects. In this paper, we analysed the error concealment algorithms, which are used in video transmission via wireless network, whic...

2000

Abstract We review error resilience techniques for real-time video transport over unreliable networks. Topics covered include an introduction to today's protocol and network environments and their characteristics, encoder error resilience tools, decoder error concealment techniques, as well as techniques that require cooperation between encoder, decoder, and the network. We provide a review of general principles of these techniques as well as specific implementations adopted by the H.

Journal of Visual Communication and Image Representation, 2005

For entropy-coded H.264/AVC video frames, a transmission error in a codeword will not only affect the underlying codeword but also may affect subsequent codewords, resulting in a great degradation of the received video frames. In this study, an error resilient coding scheme for H.264/AVC video transmission is proposed. At the encoder, for an H.264/AVC intra-coded I frame, the important data for each macroblock (MB) are extracted and embedded into the next frame by the proposed MB-interleaving slice-based data embedding scheme for I frames.

1998

ABSTRACT In this paper we review error resilience and concealment techniques which have been developed both within and outside the various videoconferencing standards. We consider the H. 324 videoconferencing standard with its accompanying lower-level H. 263 and H. 223 video and multiplexing standards, MPEG-2, and MPEG-4. We then describe an error resilience algorithm commonly used with variable length codewords, and nally review error concealment techniques that have appeared in the literature.

In this paper we describe two error-recovery approaches for MPEG encoded video over ATM networks. The first approach aims at reconstructing each lost pixel by spatial interpolation from the nearest undamaged pixels. The second approach recovers lost macroblocks by minimizing intersample variations within each block and across its boundaries. Moreover, a new technique for packing ATM cells with compressed data is also proposed.

Signal Processing: Image Communication, 2008

Video transmission over noisy channels makes error concealment an indispensable job. Utilization of data hiding for this problem provides a reserve information about the content at the receiver, while unchanging the transmitted bit-stream syntax; hence, improves the reconstructed video quality with almost no extra channel utilization. A spatial domain error concealment technique, which hides edge orientation information of a block, and a resynchronization technique, which embeds bit-length of a block into other blocks are composed. The proposed method also exploits these two techniques for detecting errors via some extra parity information. Moreover, the motion vectors between consecutive frames are also embedded into the consecutive frames for better concealment at the receiver. Finally, as a novel approach, the bit-streams are further protected against errors via channel codes and the parity bits of these codes are embedded into other slices. In this manner, implicit utilization of error correction codes improves the reconstruction quality significantly. The simulation results show that the proposed approaches perform quite promising for concealing the errors in any compressed video bitstream.

2010

Video communication through wireless channels is still a major problem due to the limitations in bandwidth and the presence of channel errors. The other limitations within the mobile networks is low transmission bit rate which demands the reduction of the used video resolution and a high efficient video compression technique. Video transmission in wireless environments is a challenging task calling for high-compression efficiency as well as a network-friendly design. The network-friendly design of H.264/AVC is addressed via the network abstraction layer that has been developed to transport the coded video data over any existing and future networks including wireless systems. Exploiting this feature, we present a modified temporal-spatial error concealment algorithm for H.264 coded video. Simulations were carried out in computing environment Matlab using the standard video-sequences.

Real-time Imaging, 2005

For entropy-coded MPEG-2 video frames, a transmission error will not only affect the underlying codeword but also may affect subsequent codewords, resulting in a great degradation of the received video frames. In this study, a hybrid error concealment scheme for MPEG-2 video transmission is proposed. The objective is to recover high-quality MPEG-2 video frames from the corresponding corrupted video frames, without increasing the transmission bit rate. In this study, transmission errors or equivalently corrupted/lost video packets in MPEG-2 video frames are detected and located by the error detection scheme proposed by Shyu and Leou [IEEE Trans. Circuits Syst. Video Technol. 10 , and then the corrupted blocks are concealed by the proposed hybrid error concealment scheme. Based on the fitness function for evaluating the candidate concealed blocks of a corrupted block, a corrupted block in an intra-coded I frame is concealed by either the spatial error concealment algorithm in H.264 or the proposed fast best neighborhood matching (BNM) algorithm. A corrupted block in an inter-coded P or B frame is concealed by the proposed fast motioncompensated BNM algorithm. Based on the simulation results obtained in this study, the proposed scheme can recover high-quality MPEG-2 video frames from the corresponding www.elsevier.com/locate/jvci (J.-J. Leou). corrupted video frames up to a packet loss rate of 20%. The performance of the proposed scheme is better than those of four existing approaches for comparison.

Signal Processing: Image Communication, 1999

In this paper we propose an error concealment algorithm for compressed video sequences. For packetization and transmission, a two layer ATM is utilized so that the location of information loss is easily detected. The coded image can be degraded due to channel error, network congestion, and switching system problems. Seriously degraded images may therefore result due to information loss represented by DCT coe$cients and motion vectors, and due to the interdependency of information in predictive coding. In order to solve the error concealment problem of intra frames, two spatially adaptive algorithms are introduced; an iterative and a recursive one. We analyze the necessity of an oriented high pass operator we introduce, and the requirement of changing the initial condition in iterative regularized recovery algorithm. Also, the convergence of iteration is analyzed. In recursive interpolation algorithm, the edge direction of the missing areas is estimated from the neighbors, and estimated edge direction is utilized for steering the direction of interpolation. For recovery of the lost motion vectors, an overlapped region matching algorithm is introduced. Several experimental results are presented.