Audio And Video Transmission System Design Based On DSP/BIOS OS

TMS320DM642 (hereinafter referred to as DM642) is a high-performance DSP processor introduced by Texas Instruments (hereinafter referred to as TI), it is mainly used for video signal processing. The processor's internal structure is Harvard architecture, its frequency is 600MHz, and the processor has a 4800MIPS processing capability. It also has a rich set of peripheral interfaces, such as video, audio, network and so on. With these features DM642 is ideal for video applications.The T264 encode lib is a widely used open-source project which is based on the H.264 standard. It has a relatively simple structure and can be implemented on multiple platforms in multiple formats of video. G.723.1 codec has a lower bit-rate and good quality of reconstruction speech, it is suitable for speech coding transmission.The goal of the project is to build an audio and video real-time capture and compression system which uses DSP as a core to send audio and video streams through the network to the receiver. Receiver program is based on PC, which implement the reception and decoding of data and real-time playback at last.This paper first makes detailed analysis of DM642 architecture, and then focus on the optimization of the encoder's memory and SIMD according to the characteristics of the platform in order to achieve real-time encoding requirement.All the tasks of DSP-side base on simple and efficient real-time operating systems DSP/BIOS which is supplied by TI. This paper analyzes and improves the driver module, and designs and implements a set of task model based on DSP/BIOS system by using visual graphical configuration interface and other tools provided by DSP/BIOS. The system can encode and send audio and video at the same time. Prioritization of tasks and the communication mechanism between tasks are analyzed in detail, making the efficient and orderly execution of each task. It makes full use of the DSP hardware resources to complete the design aim. This paper also describes the model of PC receiving end point and the implementation of audio module.Finally, this paper makes a test of the system to make sure that the operating performance of DSP side and stable operation of the entire transmission system. All this has reached the design goal.