Research And Design On HDTV Set-top Box Based On Generic DSP

In recent years, from analog black-white television to analog color television, and to digital television, television system has changed greatly. DTV(Digital Television) roots in modern digital signal processing and advanced VLSI design technology. Compared with analog television, DTV has many advantages, so it would substitute the analog television of necessity. HDTV (High Definition Television) can offer better image and sound, but to implement it more efficiently and more economically, digital format must be taken.As a consumer product, HDTV receiver Set-top Box will come into millions of families, so the research and development on it has significant effect on the society and the economy. The author presents a new idea about realizing a completely programmable HDTV Set-top Box based on generic DSP, and has implemented a cable HDTV Set-top Box solution by generic DSP together with a video decoder ASIC. The contribution of this paper takes generic DSP into the field of DTV. This is the first step to realize a completely programmable HDTV Set-top Box based on generic DSP.This solution implements cable HDTV Set-top Box based on TMS320C6701 from Texas Instrument. Generic DSP, C6701, processes kernel tasks, such as system control, demultiplex, audio decoding, video decoding control, etc. At present, generic DSP can't implement HDTV video decoding in real-time under the process capacity limit, so we use an ASIC to do this. And the front-end is implemented by an ASIC.The main part of software consists in AC-3 decoding, so in this thesis we discuss AC-3 co-decoding algorithm in detail, and implement an AC-3 decoder in C language, and then transfer it into the enviroment of TMS320C6701. In software development step, we also transfer hardware-level reference program of video decoder into the enviroment of TMS320C6701.This thesis presents a DMA and CPU co-operating multi-task schedule strategy based on DSP/BIOS, and find a solution to the key problem: how to schedule multi-tasks, such as stream input, demultiplex, video decoding control, audio decoding, audio output, etc. At present, we have implemented front-end control, stream input, demultiplex, video decoding control, audio decoding, audio output etc. software modules, and have settled real-time video decoding sub-system and real-time audio decoding sub-system.As DSP technology develops gradually, DSP can implement additional functions more and more, such as video decoding, channel decoding, channel demodulation, and so complete software programmable HDTV Set-top Box can be done. Because of the compatibility between DSP softwares, modules developed in this solution, such as front-end control, stream input, demultiplex, audio decoding, audio output can be used in the future.