| With the progress of society and the development of science and technology,there has been breakthroughs achieved in the field of semiconductor.The hardware processing speed has been significantly improved.With the influence of streaming media technology,the field of monitoring has no longer only limited to video,but also the form of simultaneous acquisition and transmission of audio and video.Because the audio and video data collected by the system is too large to transmit in a limited band width,it must be compressed and coded before transmitting.In addition,the difference in the complexity of audio and video coding algorithm,the amount of compressed data and the bandwidth of network transmission could cause delay,which will lead to out of step of audio and video on the client side.The traditional monitoring scheme based on ARM,DSP and FPGA all has some shortcomings.To solve the above problems,this paper designs a synchronous compression and transmission monitoring system of audio and video based on DaVinci processor.The system adopts DM6467 T as the core processor to make use of its unique dual-core architecture of ARM + DSP to complete the control of the whole system and the processing of audio and video data.In terms of hardware,the system adopts TLV320AIC32 and TVP5150 as the audio and video decoding chips,MT47HI28MI6RT25 E and NAND01GW3B2AZA6 E as the storage chips,and KSZ8001 as the network transmission chips.In terms of software,the system adopts H.264 and AAC as the audio and video data compression algorithm of the system,and proposes the synchronous control method based on RTP protocol timestamp information and RTCP protocol feedback message.The Da Vinci software platform is established with the development kit provided by TI to establish.The whole system is programmed under Linux system.The first step is collecting the audio and video data according to V4L2 and ALSA framework and compressing the data by invoking the algorithm of DSP terminal with CE module.Next step is packaging and sending data byORTP database,and adjusting the transmission rate and playing status of audio and video data according to the occupation status of buffer area of RTP timestamp information and RTCP message feedback at the receiving end.Therefore,the system could achieve synchronous play of audio and video.The system test result shows that the decoded audio and video data has a high quality and good synchronization effect,and the system delay is about 200 ms.The above result shows that the synchronous compression and transmission monitoring system of audio and video designed in this paper meets the practical application requirements. |
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