Design And Implementation Of Audio And Video Signals Acquisition Compression And Transmission System

With the development of digital technology,audio and video technology is entering into people's work and life,improving people's work efficiency and living standards.Audio and video system include the processing,storage and output or display of sounds and images that has widely been used in communications,entertainment,and security.Currently,audio and video system has been used in video surveillance,ATM,medical devices,and many handheld devices.With the widely use of audio and video technology on embedded platforms,embedded audio and video acquisition and transmission systems have become a research hotspot.The audio and video signal acquisition compression and transmission system is designed and implemented in this paper.The main contents are as follows:Adopting TI TMS320DM365 processor,equipped with corresponding peripherals,the system can acquire audio and video signals,and convert analog signal into digital signal,then compress and package the digital audio and video data and transmit it.And on this basis,many other functions have been extended.By studying embedded Linux software programming technology and Da Vinci technology,the acquisition and compression of audio and video signals are realized in this paper.Firstly,the embedded Linux system is built on the embedded hardware platform,Then the DVSDK(audio and video software development kit)of Da Vinci technology is analyzed in detail,and the multi-threading program including video capture thread,video coding thread,video write thread and audio thread is designed,realizing the acquisition and compression of audio and video signals.And further developed on the basis of this,realizes the functions of parameter configuration and video added time subtitles.Based on the FFmpeg audio and video framework,the packaging and transmission of audio and video compressed data is designed and implemented.The TS stream format and the structure of the FFmpeg are analyzed.By invoking the function in FFmpeg,the program can pakage the audio compressed code stream and the video compressed code stream into TS streams,and realize audio and video synchronization.Then,by the method operating data in memory,combined with the EMIF driver,packaged TS stream is transmitted from the DSP to the FPGA through the EMIF.Finally,the whole system was tested,and the audio and video signals were acquired,compressed and packaged correctly and efficiently,and transmitted from the DM365 to the FPGA.Then the FPGA buffered the audio and video data and transmitted it to the host computer for play.And realize the configuration of the audio and video parameters of the upper computer and the function of adding time subtitles to the video.The system uses Da Vinci technology hardware and software and FFmpeg audio and video framework,enabling developers to achieve secondary development more easily and quickly,and has a good portability.