Impact of slice size for SVC coding efficiency and error resilience

Abstract

Scalable Video Coding (SVC) as an extension to the H.264/AVC standard enables adaptive video transmission, where several types of sub-streams can be decoded from a single encoded stream. The same video content can be streamed to low bit rate mobile phones with low quality as well as high bit rate televisions with extremely high quality. However, strict real-time requirements and unreliable transmission channel can cause packet losses, which means that sufficient error protection and concealment methods are needed. One of the error protection techniques in the encoder enables division of a picture into slices. Introduction of slices will decrease the coding efficiency but at the same time it will improve resilience against transmission errors. In this paper, we try to find a trade-off between the number of slices and coding efficiency for H.264/SVC to be used for video streaming in error-prone networks. In addition to coding efficiency, the selected slice size will affect on error resilience and error propagation inside the video stream. This means that the optimal slice size should not only provide sufficient coding efficiency but it should also provide a good error concealment ratio in relation to packet losses. This paper evaluates the trade-off between the coding efficiency and error resilience of H.264/SVC. The simulation results presented in the paper indicate that a minor increase of the amount of slices per picture greatly improves the error resilience but does not reduce the coding efficiency greatly. The best trade-off in our simulations is achieved by using three slices in a layer. © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering.