Cross-Layer Detection of Visual Impairments in H.264/AVC Video Sequences streamed over UMTS Networks

Incorrectly received packets in low-rate video sequences result in the loss of considerably large picture areas that have to be concealed. The performance of error concealment decreases with the size of the interpolated picture area. The incorrectly received packets may still contain some correct information that can be exploited at the decoder. In this work we propose the utilization of information from the link layer of UMTS (universal mobile telecommunications System) at the application layer for better pre-localization of errors in the bitstream domain. Syntax check together with the detection of impairments in the pixel domain decide which part of the incorrectly received packets will be concealed. We evaluate the results using error traces from the live UMTS network and H.264/AVC (advanced video coding) encoded video stream. Apart from reduced complexity facilitated by the cross-layer approach, the proposed method gains 1.09 dBs of Y-PSNR compared to a slice rejection mechanism.