Study And Realization Of Digital Audio On Demand Terminal

Currently, domestic naval ships have not equipped recreational facilities generally, even similar equipment such as VCD, DVD TV, ect, equipped in a few naval ships, are only in the cabin which is larger space and playing the ways of passive listening and watching, based on analog signals. Large in size and weight, poor in stability, and limited in the users to watch due to the space and time, such equipment is actually ineffective.Digital Audio Video on Demand System adopts the technology of computers, network communications, multimedia and digital coding and decoding. It transmits the content-rich digital audio and video program to the beds of each cabins in the ship, provides services of real-time, and interactive audio and video programs for shipman and to accommodate their long-boring maritime;At the same time, the equipment can be used as an aid by captain to communicated his order.In this paper, Digital Audio on Demand Terminals used in Digital Audio Video on Demand System was designed. The Terminal adopts Windows CE.net operating system based on the ARM9 core embedded hardware platform, achieves the MP3 on Demand in LAN, MP3 decoding and playing utilized DirectShow technology. We use TCP to transmit MP3 files in the LAN because the file is large, and it needs continous and stable transmission. Compared with the Audio file, the control data which is transmited between server and terminals is little. And so we use UDP as communication way whith is real-time. In addition, by the approach of the combination of software and hardware, the captain's command could be communicated in LAN real-time. On the basis of exploring the latest achievements in this field, the paper discusses the conception and designing plan of the Digital Audio on Demand Terminals, introduces in detail about the system design, operating principles, hardware design, software design, and debugging to the terminal.Experiments have shown that the Digital Audio on Demand Terminals is excellent in tone, could accept captain's instructions timely, and could fully meet the requirement in ships. In addition, it has the originality of the technology application by using the embedded system in Audio on Demand System.