【作者】 任国涛；

【导师】 王养利；

【作者基本信息】 西安电子科技大学 ， 计算机应用技术， 2004， 硕士

【摘要】 人们利用便携终端通过IP网络传输视频信息的需求越来越多，为了实现这个目标，有两个问题需要解决：1．编码方法要简单高效。方法简单，容易用硬件实现，且功耗低；方法高效，可以有效的利用网络带宽实时传输视频；2．编码要有好的鲁棒性，以适应IP网络的传输特性，在出现丢包的情况下，能够实时恢复出较好的图像质量。 针对上述两个问题，本文提出基于3D-DCT的多描述编码方案，它由分块、3D-DCT变换、量化、MDSQ编码、RLE编码和熵编码等部分组成。3D-DCT变换编码，没有运动补偿，运算复杂度低，通过优化量化表和扫描顺序，使3D-DCT达到了令人满意的压缩比和图像质量。多描述编码把信源变成多个描述，每个描述都可以恢复出一定质量的信源，降低了某个描述丢失所带来的损失，提高了编码的鲁棒性。 实验仿真表明3D-DCT和多描述相结合的视频编码方案，在简单高效的同时具有很强的抗误码能力，很好的解决了视频传输在便携终端上应用的问题。更多还原

【Abstract】 The need of transmission of video via IP networks becomes more and more. In order to achieve this goal, two problems should be solved. Firstly, the coding method should be simple and high efficiency. Simple method can be implemented by hardware easily, and requires lower power. High efficiency can decrease network bandwidth needed for communication. Secondly, the coding is robust, i.e, it is fit for transmission via IP networks. Even when some packets are lost during transmission, acceptable quality of video can still be reconstructed.To solve the above-mentioned two problems, this paper proposes a multiple description video coding method based on 3D-DCT and MDSQ. The system consists of several parts: video volume formation, 3D-DCT, MDSQ, RLE coding and entropy coding and so on. 3D-DCT is a symmetrical transform so the encoder and the decoder has similar computational complexity. There is no motion compensation in the proposed scheme, so the method is simple and can be easily implemented in hardware. Through the optimization of the quantization volume and scanning order, the 3D-DCT based video coding scheme can obtain satisfactory results both in compression ratio and in PSNR. Multiple description coding divides the source information into several descriptions, each description could reconstruct acceptable source information, and reduced the loss caused by the lost of some descriptions, and improve the reliability of the video coding method.Experiment results show that the 3D-DCT based multiple description coding scheme has a finer robustness while being simple and highly efficient. The scheme is suitable for video transmission on portable terminal.更多还原