Robust video coding based on hybrid hierarchical B pictures

Compressed video streams transmitted over error-prone environments are usually corrupted by transmission errors. Error-concealment techniques can be used to recover the lost information. In this paper, a hybrid model is proposed to improve the error-concealment performance. The model combines two hierarchical B-picture coding structures such that key-frames, reference B frames, or even nonreference B frames have buddy frames to serve as their data recovery frames when they are lost. With buddy frames, the distance between a lost frame and its recovering frame can be substantially reduced. In addition, an improved estimation method is also proposed to further increase the accuracy of recovering motion. Error-concealment performance can thus be significantly improved with little bit-rate redundancy. We have conducted experiments to compare its performance with other methods, and the results show that the proposed hybrid model outperforms these competed methods. The advantages of the proposed hybrid model are demonstrated in error-free and packet-loss environments.