針對H.264/AVC標準之多重描述視訊編碼
摘要
With the advances of digital video technology and the rapid growth of the Internet and wireless networks, video communication has been gaining in importance. Emerging applications includes: video conferencing, digital video broadcasting, peer-to-peer video transmission, etc. Extensive works on the Internet routing algorithms as well as the video coding techniques have been conducted to provide reliable video transmis-sion over error-prone environments. Multiple description coding (MDC) has emerged as a promising approach to combat packet losses and enhance error-concealment in video transmission. By using MDC, a video sequence is encoded into multiple independently decodable descrip-tions. As more descriptions are received at the decoder, the reconstructed video with better quality is obtained. These multiple description streams are transmitted along multiple paths to provide reliable transmission over packet-networks. The efficiency of an MDC scheme depends on the way of introducing redundancy into individual descriptions. An H.264/AVC-based multiple description video coding scheme is proposed. The proposed MDC scheme utilizes the advanced video coding tools and features pro-vided in H.264/AVC, including slice groups, variable block-size motion compensation, and multiple reference frames. Slice groups are adopted to produce multiple descrip-tions. Spatial and temporal correlations between neighboring macroblocks in video frames are exploited to achieve efficient redundancy coding. From the experimental results, the proposed MDC scheme has superior rate-distortion (R-D) performance to previous slice-group based MDC scheme. A complete error-concealment mechanism is also supported by the proposed MDC scheme to handle packet losses. Combined with the current Internet routing algorithms, e.g. an over-lay network, the proposed MDC scheme is capable of providing a practical solution for video transmission.