Shape refreshment need metric for object-based resilient video coding

Although there are several techniques that video encoders may use to improve error resilience, it is largely recognized that intra coding refreshment plays a major role. This technique is especially useful for video encoders that rely on predictive (inter) coding to remove temporal redundancy because, in these conditions, the decoded quality can decay very rapidly due to error propagation if errors occur in the transmission or storage of the coded streams. Therefore, in order to avoid error propagation for too long a time, the encoder can use a coding refreshment scheme to refresh the decoding process and stop (spatial and temporal) error propagation. In the context of object-based video coding, the video encoder can apply intra coding refreshment to both the shape and the texture data. A shape refreshment need metric is proposed which can be used by object-based video encoders, notably MPEG-4 video encoders, to determine when the shape of a given video object should be refreshed in order to improve the decoded video quality.