Error Concealment Mode Research Articles

Error Concealment-Aware Encoding for Robust Video Transmission

In this paper an error concealment (EC)-aware encoding scheme is proposed to improve the quality of decoded video in broadcast environments subject to transmission errors and data loss. The proposed scheme is based on a scalable coding approach where the best EC methods to be used at the decoder are optimally determined at the encoder and signalled to the decoder through supplemental enhancement information messages. Such optimal EC modes are found by simulating transmission losses, followed by a Lagrangian optimization of the signalling rate—EC distortion cost. A generalized saliency-weighted distortion is used and the residue between coded frames and their EC substitutes is encoded using a rate-controlled enhancement layer. When data loss occurs the signalling information is used by the decoder to improve the reconstruction quality. The simulation results show that the proposed method achieves consistent quality gains in comparison with other reference methods and previous works. Using only the EC mode signalling, i.e., without any residue transmitted in the enhancement layer, an average PSNR gain up to 2.95 dB is achieved, while using the full EC-aware scheme, i.e., including residue encoded in the enhancement layer, the proposed scheme outperforms other comparable methods, with a PSNR gain up to 3.79 dB.

Robust real-time UHD video streaming system using scalable high efficiency video coding

With a new video coding standard high efficiency video coding (HEVC), the ultra high definition (UHD) TV service with robust video streaming technology is emerging in the TV industry. This paper addresses the system architecture for the UHD video streaming and proposes three main ideas: (i) picture prioritization method, (ii) error concealment mode signaling (ECMS), and (iii) Tile complexity-based parallel video processing. In the experiments using HEVC reference model conducted, the proposed picture prioritization method shows the gains in video quality from 2.2 to 7.5 dB in Y-PSNR, and the error concealment mode signaling gains from 0.2 to 2.5 dB in Y-PSNR, with corresponding subjective improvements. In addition, proposed parallel processing method for real-time decoding shows around 20% decoding speed up gain.

Pixel-level Matching Based Multi-hypothesis Error Concealment Modes for Wireless 3D H.264/MVC Communication

3D multi-view video (MVV) is multiple video streams shot by several cameras around a single scene simultaneously. Therefore it is an urgent task to achieve high 3D MVV compression to meet future bandwidth constraints while maintaining a high reception quality. 3D MVV coded bit-streams that are transmitted over wireless network can suffer from error propagation in the space, time and view domains. Error concealment (EC) algorithms have the advantage of improving the received 3D video quality without any modifications in the transmission rate or in the encoder hardware or software. To improve the quality of reconstructed 3D MVV, we propose an efficient adaptive EC algorithm with multi-hypothesis modes to conceal the erroneous Macro-Blocks (MBs) of intra-coded and inter-coded frames by exploiting the spatial, temporal and inter-view correlations between frames and views. Our proposed algorithm adapts to 3D MVV motion features and to the error locations. The lost MBs are optimally recovered by utilizing motion and disparity matching between frames and views on pixel-by-pixel matching basis. Our simulation results show that the proposed adaptive multi-hypothesis EC algorithm can significantly improve the objective and subjective 3D MVV quality.

Error concealment mode signaling for robust mobile video transmission

Error concealment (EC) is essential for a video transmission system over the error prone networks. However, it is very difficult to find the best EC method among many EC methods without the original pictures. This is the limitation of the EC method that only works at a video decoder side. Thus, this paper proposes a new method that signals best EC mode(s) which is calculated and determined at an encoder side to a decoder. When the experiments were conducted, gains in video quality vary from 0.2 to 2.5dB in PSNR.

Motion vector recovery for inter-frame error concealment in H.264

Concerning the video quality decline caused by damaged macroblocks in video transmission,this paper modified the boundary matching algorithm by adopting the interlaced weighted double error concealment scheme,inducted the motion vector estimation selectively,and used 8×8 subblocks correlation error concealment mode when the boundary matching error of the predictive block was higher than a given threshold.Experimental results show that the proposed algorithm could averagely raise the PSNR about 1 dB and correspondingly improve the decoded video quality effectively.

Variable Block Size Motion Vector Retrieval Schemes for H.264 Inter Frame Error Concealment

With the ubiquitous application of Internet and wireless networks, H.264 video communication becomes more and more common. However, due to the high-efficiently predictive coding and the variable length entropy coding, it is more sensitive to transmission errors. The current error concealment (EC) scheme, which utilizes the spatial and temporal correlations to conceal the corrupted region, produces unsatisfied boundary artifacts. In this paper, first we propose variable block size error concealment (VBSEC) scheme inspired by variable block size motion estimation (VBSME) in H.264. This scheme provides four EC modes and four sub-block partitions. The whole corrupted macro-block (MB) will be divided into variable block size adaptively according to the actual motion. More precise motion vectors (MV) will be predicted for each sub-block. Then MV refinement (MVR) scheme is proposed to refine the MV of the heterogeneous sub-block by utilizing three step search (TSS) algorithm adaptively. Both VBSEC and MVR are based on our directional spatio-temporal boundary matching algorithm (DSTBMA). By utilizing these schemes, we can reconstruct the corrupted MB in the inter frame more accurately. The experimental results show that our proposed scheme can obtain better objective and subjective EC quality, respectively compared with the boundary matching algorithm (BMA) adopted in the JM11.0 reference software, spatio-temporal boundary matching algorithm (STBMA) and other comparable EC methods.

Dynamic Multi-mode Switching Error Concealment Algorithm for H.264/AVC Video Applications

In video communication based consumer device applications, the compressed video is extremely fragile to transmission errors due to channel noise. Error concealment (EC) is an efficient way to recover a damaged video sequence. The existing EC algorithms for compressed video typically apply uniform EC mode to entire video sequence regardless of frame features, or lack in sensible mode-switching considerations. This paper proposes a new dynamic multi-mode switching (DMS) EC algorithm. The proposed algorithm provides several EC modes for intra- and inter- frames. The proposed smart decoder is able to adaptively apply these modes in different situations. The mode switching in DMS depends on the spatial/temporal correlation, estimated edge features of the corrupted Macroblock (MB), the smoothness of the reconstructed MB and etc. The proposed DMS algorithm has been evaluated and compared with 3 classical EC algorithms. The experimental results show that the DMS algorithm can achieve significant gains in peak signal noise ratio (PSNR) and therefore improves the decoded picture quality in video applications.