可分级编码是解决Internet流视频应用中网络带宽不断波动的一种有效方法，所以MPEG-4标准中采用了FGS(fine granularity scalability)编码方法来获得精细颗粒可分级能力，但其代价是编码效率的下降。为解决此问题，现提出在增强层中采用运动补偿的MC加FGS(motion compensation加FGS)结构，用于去除FGS方案中增强层在时域上的冗余，以提高FGS方案编码效率的双环和单环两种方法。在比较了两种结构各自的优缺点后，选定了一种复杂度小、实现简单、效率高的单环结构，并提出了对单环结构的缺陷进行改善的方法。实验结果表明，该方法的编码性能优于MPEG-4 FGS方法。

Transmitting video streaming over Internet is a challenging problem because the bandwidth of network varies all the time. Scalable coding seems to be an effective solution to resolve the bandwidth varying on the streaming video application over Internet. Though traditional scalable video coding schemes get scalability, the scalability is coarse and need much more memory expense. To obtain fine granularity scalability, the MPEG-4 video coding standard adopts FGS coding scheme. It permits bitstreams after being coded be truncated and transmitted arbitrarily with the available bandwidth. However, the fine granularity scalability of the FGS is obtained at sacrifice of coding efficiency. The reason that causes the FGS coding scheme's coding efficiency is, there exists much temporal redundancy on the enhancememt layer. In this paper, two MC FGS structure based on using motion compensation on the enhancement layer are developed to get higher coding efficiency. Both of them exploit the temporal redundancy of the enhancement layer. After comparing both structures, one is recommended by this paper. The experimental results prove that the performance of scheme presented by this paper is better than that of MPEG-4 FGS.