Design And Implementation Of High Definition Real-time Live System Based On Ffmpeg

At present,the common live broadcast system in our life is mostly used streaming media data block-by-block design,and do the secondary processing for the flow data in the server side,the live delay of such live broadcast system is often relatively high,at the same time,its live effect has been criticized because of using a low quality image compression coding algorithm.In order to overcome the problems of such live system,this paper designed and realized a set of high-definition low-latency live broadcast system,it is a important role in high requirement applications for clarity and real-time such as emergency command,live broadcast,real-time meetings.The paper analyzed and introduced the audio and video processing technology and the streaming media transmission protocol used in HD real-time live broadcast system at first,and then,studied existing problems and shortcomings in live broadcast system,by optimizing and reforming FFmpeg audio and video processing process,designed and realized real-time live data acquisition,video color space conversion,video decoding display,audio data re-sampling,multithreading audio and video HD encoding,streaming media data transmission and live data server forwarding and other functions.The following improvements proceeded at the same time in the realization process for the problems that the low quality audio and video,larger network latency and other issues in existing live broadcast system.1.In the process of equipment signal acquisition,to achieve the best balance of audio and video perception and system processing efficiency by controlling of thdacquisition rate.And the YUV color space conversion did for video data according to more sensitive characteristics of human eye on the brightness of the information.2.Design and realized audio and video decoding data buffers,the multithread synchronization and SDL display of video data are completed through the critical area resource and the read buffer,which improved fluency and stability of audio and video codec processing.3.By using high-definition H.264 video encoding and AAC advanced audio coding technology,improved the quality of live audio and video and reduce the network bandwidth pressure,done a re-sampling process for audio noise problems at the same time,eliminated the noise in the decoding and acquisition process.4.Timestamp synchronization technology is used to synchronize audio and video data,by writing the file stream to transmit live data frame by frame network based on RTMP streaming media transmission protocol,it greatly reduced delay of the data transmission.5.Build RTMP streaming media server Based on Nginx,that will forward the received live data immediately to the client,it not only improves the processing capacity of live server in face of high concurrent requests,but also reduces the system’s network latency.The users will also be able to watch the live screen on the Flash page,improved the convenience of client deployment.At last,after the functional test and output audio and video quality evaluation of the live system,it is shown that designed and realized HD real-time live system in this paper is functioning correctly,running smoothly,the live picture is clear and the broadcast delay is kept low.