Macroblock-based algorithm for dual-bitstream MPEG video streaming with VCR functionalities

Reverse playback is the most common video cassette recording (VCR) functions in many digital video players. However, the predictive processing techniques employed in MPEG severely complicate the reverse-play operation. One approach to achieve the reverse playback is to store an additional backwardencoded bitstream into the server. Once the client requests a backward-play operation, the server will select an appropriate frame for the client from either the forward or backward-encoded bitstream by considering the cost of network bandwidth and the decoder complexity. Unfortunately, the forward and backwardencoded bistreams are encoded separately. The frame that has previously decoded by the client may not exactly identical to the reference of the current selected frame and the drift problem is occurred. In this paper, we propose a macroblock-based approach to alleviate the drift problem with the minimal requirements on the network bandwidth and the decoder complexity. The novel macroblock-based techniques are used to manipulate the necessary macroblocks in the compressed-domain and the server then sends the processed macroblocks to the client machine. Experimental results show that, as compared to the conventional dual-bitstream system, the new streaming system enhances the quality of the reconstructed frame significantly.