In modern real-time communication systems involving video transmissions, the compressed video bit-streams are transmitted on networks that are sometimes unreliable and error-prone. Therefore, packet loss of encoded video over such networks may cause a strong visual degradation in the reproduction of video content at the receiver. Error concealment methods aim to reduce such degradations by making use of the redundancies in the temporal and spatial domain and attempt to recover the lost data based on the correctly received data without increasing the transmission overhead.

In this work, we propose efficient algorithms for improved error concealment of the corrupted H.264/AVC video sequences. We first investigate the widely used directional spatial error concealment scheme and report suggestions for its better usage. Next, using the information of Intra prediction modes from the coded bit-stream, a spatial error concealment method with reduced computational complexity is developed, which improves the concealment performance and the visual quality of the damaged Intra frames. In addition, we propose a content-adaptive temporal error concealment method for packet losses occurring in the Inter frames of the video sequence. Using the mode information of the neighboring macroblocks, we partition a lost macroblock by adaptively selecting the most suitable of eight partition types to guarantee smoothness in the reconstructed picture. We also exploit the concept of overlapped block motion compensation to avoid spatial discontinuities.

Stefan CIF Inter frame @ 10% loss rate:

   

a) Concealed with ABS, PSNR = 26.35 dB, SSIM = 0.8726 b) Concealed with CAMP, PSNR = 27.63 dB, SSIM = 0.9432

Publications:

1. Santosh Chapaneri and Jeffrey J. Rodriguez, "Content-Adaptive Macroblock Partitioning Scheme For Error Concealment Of H.264/AVC Coded Video," 2009 IEEE Intl. Conf. on Image Processing, Cairo, Egypt, Nov. 7-10, 2009, pp. 917-920. [ PDF ]
   
   
2. Santosh Chapaneri and Jeffrey J. Rodriguez, "Low complexity error concealment scheme for intra-frames in H.264/AVC," 2009 IEEE Intl. Conf. on Image Processing, Cairo, Egypt, Nov. 7-10, 2009, pp. 925-928. [ PDF ]
   
   
3. Santosh Chapaneri and Jeffrey J. Rodriguez, "Content-Adaptive Temporal Error Concealment Scheme for H.264/AVC Video Communication," ICGST International Journal on Graphics, Vision and Image Processing, GVIP, Vol. 10, no. 2, June 2010, pp.9-18. [ PDF ]