Video Transcoding From MPEG-2 To MPEG-4

With the development of multimedia network communication, networks will bear more and more multimedia services. As the multimedia data with different bit rate, definition, and standards transmitting over heterogenous networks and accessing equipments and receiving by equipments with diverse capability, many problems of mismatch between data rate and bandwidth would often appear. To solve it, video transcoding technique is usually adopted. And in order to realize seamless connection between distinct access equipments and between diverse multimedia data, video transcoding technique turns out to be much more important.Video transcoding which is the operation of converting a video from one format into another format for different purposes, has been extensively studied in rencent years. A format is defined by such characteristics as the bit rate, frame rate, spatial resolution, coding syntax, and content etc. Generally, exsiting video transcoding schemes can be classified into two categories: pixel domain transcoding and discrete cosine transform (DCT) domain transcoding, which the latter is preferred due to keeping high-quanlity performance and its low computational complexity: DCT, inverse DCT and motion estimation are skipped in DCT-based methods.In this thesis, we concentrate on the problem of video transcoding from MPEG-2 to MPEG-4 in the DCT domain, including down-sampling. The key techniques in the DCT domain video...