Video Transcoding And Its Application

With the developement of video coding technologies, more and more digital video contents exist in the coded form (e.g. MPEG, H.26x or others) for saving storage and facilitating content exchange. Transcoding coded video contents from one format to another, from one bit rate to another and from one resolution to another is indispensable in many multimedia applications, such as digital video broadcasting, video on demand (VOD), teleconferencing and long distance learning, and so on. This dissertation mainly investigates video transcoding techniques for MPEG bitstreams. The issues for our research include how to fast transcode MPEG video bitstream from high bitrate to low bitrate, how to transcode MPEG transport stream to MPEG program stream, and how to transcode YUV422 video bitsream to YUV420 video bitstream. Moreover, video transcoding technique for MPEG video bitstream cutting & pasting is also addressed. Detail research contents are given as follows.1. Proposes a fast video transcoding architecture with limited drifting error. It is used for bit-rate reduction video transcoding. With this video transcoding architecture, the picture quality obtained from the proposed transcoder is close to that of the traditional closed-loop one, while the transcoding speed is even faster than the transditional open-loop one. Furthermore, the proposed transcoder provides the desired flexibility between picture quality and transcoding complexity in CPU-awareness applications.2. Proposes a system level MPEG transcoding scheme for converting MPEG transport stream (TS) to MPEG program stream (PS). The key point for this system level transcoding scheme is transcoding constant-bit-rate (CBR) video bitstream to variable-bit-rate (VBR) video bitstream. Two different solutions are addressed. One is designed for offline transcoding, which has better visual quality but high implemetion cost. The other is designed for real-time transcoding, which also has better visual qualitiy compared with transcoding CBR bitstream to CBR bitstream at the same bitrate.3. Proposes video transcoding technique for cutting & pasting MPEG video...