The Implementation Of PVR Function And The Study Of The Key Technology On The Digital STB

With the rapid development of digital television's transition, users of digital television, especially high-end users, make greater requirement for the PVR STB. However, as the technology of PVR STB is complex, whose demanding for the hard disk is high, there are few manufacturers who can provide the maturational PVR STB, which raises the new study of PVR STB.Thereof, by the in-depth study of SC2005 platform and MPEG-2 system layer, in combination with the platform's standard ATA interface, the DMA2 way to transmit data is used, and the file storage mixed of audio and video data is chosen, by which the basic functions of the program recording, playback, timeshifting and so on is realized.The key technology to this PVR STB is audio and video synchronization and the realization of the skipping forward or backward. Through the research of MPEG-2 video and audio synchronization principle based on the digital STB platform, and the analysis of the Video and Audio's out of synchronization in PVR systems, the PTS information is used for adjustment. In combination with the decoder of the SC2005 platform, an adjustment algorithm is adopted to solve the Video and Audio's out of synchronization. By utilizing the SC2005 characteristics of detecting a "pattern" Information in the data stream and analyzing the MPEG-2 video stream sequence, a way of detecting the I frame information is adopted. The indexing mechanism of the I frame information is established. When skipping forward or backward, the skipping function is realized by indexing I frame information. In order to improve search efficiency, the dynamic caching mechanism is used. A higher speed effect of fast or slow playing is achieved.The PVR STB has high cost performance. It is one of the outstanding high-end digital STB. With the rapid development of the domestic digital TV, the PVR STB will have a broad market prospect.