The System Design And Implement Of Video Decoder In IP Set-top Box

In recent years, domestic and foreign wide bands network development swift and violent, the IP multimedia technology is mature day after day. The digital technology, computer technology combine with the Domestic electric appliances product gradually.The IP set-top box was born under this background.At present the most IP set-top box products select the method of hardware decoder. The promotion ability of those products are bad, and cannot satisfy the the rapid development of audio and video codec technology. How to construct a flexible, easy to promote, and low cost IP set-top box system is the main goal this topic .Through researching the present mainstream IP set-top box hardware system, designed an IP set-top box system which based on the ADI Blackfin series DSP, and chose the BF561 processor as the system core processor. The system, not only has necessary Ethernet interface, audio and video output, keyboard mouse connection interface, but also has hard disk IDE,CF card and infrared interfaces which improves the system expansion ability. At the same time, the author studied the MPEG-4 video codec algorithm, transplanted the MPEG-4 video decoder to the Blackfin processor and did lots of optimization work. Now the embedded MPEG-4 decoder can work in realtime on the Blackfin processor, the image resolution achieves D1 (720x576).This article has mainly discussed IP set-top box hardware design which based on the DSP as well as the realization of video decoder software. And especially dissertates key methods aimed at solving the real-time problem of the system. At last, the test results are proposed , which prove that the video decoder arrives at the design goal of the project. This system has the low cost ,easy to promote, and the short development cycle characteristic, and has the very good application prospect. DSP video decoder realization, not only apply on the IP set-top box, but also can transplant to the portable media player (PMP), the video conference terminal, the surveillance terminal and so on, the application scope is extremely widespread.