Efficient Alternative to Intra Refresh using Reliable Reference Frames

Motion compensated prediction of video results in decoder-side error propagation (EP) in the presence of channel losses. Progressive intra-refresh methods control the EP, but lead to a drop in coding efficiency (CE). Error-resilient video coding schemes using multiple reference frames have been proposed earlier to achieve a better CE. Some schemes (e.g. ACK-based) tend to be conservative at the expense of CE. Methods using probabilistic models and motion tracking to estimate the decoder state offer better CE, but do not take care of the time taken to recover from losses and the EP due to the use of unreliable reference frames. In this paper, we propose an alternative to intra-refresh that controls the EP and overcomes the CE loss through the use of reliable (i.e. near drift-free) reference frames to code the refresh macroblocks. The proposed scheme has been validated through integration into a ITU-T H.264 encoder and has been shown to give a CE gain of up to 1.5dB. Further, it is of low-complexity and suited for implementation on embedded platforms.