We have designed and implemented a video semantic summarization system, which includes an MPEG-7 compliant annotation interface, a semantic summarization middleware, a real-time MPEG-1/2 video transcoder on PCs, and an application interface on color/black-and-white Palm-OS PDAs. We designed a video annotation tool, VideoAnn, to annotate semantic labels associated with video shots. Videos are first segmentated into shots based on their visual-audio characteristics. They are played back using an interactive interface, which facilitate and fasten the annotation process. Users can annotate the video content with the units of temporal shots or spatial regions. The annotated results are stored in the MPEG-7 XML format. We also designed and implemented a video transmission system, Universal Tuner, for wireless video streaming. This system transcodes MPEG-1/2 videos or live TV broadcasting videos to the BW or indexed color Palm OS devices. In our system, the complexity of multimedia compression and decompression algorithms is adaptively partitioned between the encoder and decoder. In the client end, users can access the summarized video based on their preferences, time, keywords, as well as the transmission bandwidth and the remaining battery power on the pervasive devices.