Error Concealment in the Network Abstraction Layer for Medium Grain Scalability of SVC This paper presents an error concealment method for medium grain scalability (MGS) of the scalable extension of H.264AVC. Instead of reconstructing a lost frame using a typically computeintensive error concealment method, in this method, a lightweight decoder preprocessor generates a valid bit stream from the available network abstraction layer (NAL) units in case that MGS layers are used. NAL unit header and slice header are parsed to detect the loss of a NAL unit from MGS layers. Modifications are applied to NAL unit header or slice header if some NAL units of MGS layers are lost. Hence, the number of additional packets that a decoder has to discard as a result of a packet loss is minimized. The proposed method requires low computational cost which is suitable for realtime video streaming. The experimental results demonstrate that the proposed method achieves an improvement of 2.16 dB compared to the NAL unit removal method at 5% packet loss rate. The proposed method can work complementary with other error concealment schemes for a wholeframe loss or serve as a preprocessor to a standard decoder.

Fine grained loss protection for robust internet video streaming Several embedded video coding schemes have been recently developed for multimedia streaming over IP. In particular, FineGranularScalability (FGS) video coding has been recently adopted by the MPEG4 standard as the corevideocompression method for streaming applications. From its inception, the FGS scalability structure was designed to be packetloss resilient especially under Unequal Packetloss Protection (UPP). In this paper, we introduce the notion of Fine Grained Loss Protection (FGLP), which provides UPP within the FGS enhancementlayer, and we develop an analytical framework for evaluating FGLP bounds. Based on these bounds, we show the impact of applying finegrained protection to the FGS enhancementlayer for different types of video sequences and over a wide range of bitrates and packetloss ratios. Subsequently, the FGLP framework has been implemented using forward error correction codes and its performance for Internet video streaming has been evaluated. As illustrated by our extensive simulation results, finegrained loss protection for the FGS enhancementlayer can provide significant resilience under moderatetohigh packetloss ratios (e.g. 510%).