基于Freescale i.MX6的VPU视频编解码系统的设计与实现

发布时间：2018-11-09 21:00

【摘要】：网络和通信技术的发展突飞猛进,多媒体和音/视频编解码技术日趋成熟,大量多媒体通信业务涌现出来。VoIP技术可以实现PC与电话的语音和视频通讯,同时可完成文字、图像的传送,并进一步拓展在远程医疗、远程教育等实际场景中应用。随着VoIP技术和市场的不断成熟以及移动互联网的普及,在PC系统上运行远程医疗已经不能满足用户在移动性和便携性方面的需求,所以展开在嵌入式系统上的研究就十分有必要了。本文基于Freescale i.MX6DualLite多媒体处理器,通过对远程医疗和对SIP网络电话VoIP软终端Linphone开源项目的分析研究,设计了远程医疗协助系统,实现向远程医生或专家请求医疗协助。为了解决在益体机端使用远程医疗的视频通话中CPU使用率过高及其引起的声音不连续,画面不流畅等问题,制定了i.MX6的VPU硬解码特性实现H.264编解码器,并将其整合融入到Linphone中的系统解决方案,然后应用在远程医疗协助系统中。最后经过测试,系统实现了音视频呼叫远程医生专家请求协助,运行稳定。同时H.264编解码器在远程医疗协助系统中表现良好,用户体验和音视频的性能提升都达到了需求和预期效果,在分辨率设为CIF 352*288,带宽限制设为350-380Kbit/s的局域网环境下,CPU使用率控制在30%以下,延迟时间不超过1s,音视频通话流畅。同时也表明利用i.MX6的VPU硬件特性进行视频编解码的优化方案切实可行,对其他类似系统实现具有一定的参考价值。
[Abstract]:With the rapid development of network and communication technology, multimedia and audio / video coding and decoding technology is becoming more and more mature, and a large number of multimedia communication services have emerged. VoIP technology can realize voice and video communication between PC and telephone, at the same time, it can complete text. Image transmission, and further expansion in telemedicine, distance education and other practical applications. With the maturity of VoIP technology and market and the popularity of mobile Internet, telemedicine running on PC system can no longer meet the needs of users in mobility and portability. So the research on embedded system is very necessary. Based on the Freescale i.MX6DualLite multimedia processor, this paper designs a telemedicine assistance system based on the analysis of telemedicine and the open source project of SIP network telephone VoIP soft terminal Linphone, which can request medical assistance from remote doctors or experts. In order to solve the problems of high CPU usage and the discontinuous sound and unsmooth picture caused by using telemedicine in the video call, the VPU hard decoding characteristic of i.MX6 is developed to realize the H.264 codec. It is integrated into the system solution in Linphone and then applied to telemedicine assistance system. Finally, after testing, the system realizes audio and video calling remote doctor expert for assistance, running stably. At the same time, the H.264 codec performs well in the telemedicine assistance system. The user experience and the performance improvement of audio and video meet the requirements and expected results. The resolution is set to CIF 352C288. Under the local area network environment with bandwidth limit set to 350-380Kbit/s, CPU usage is controlled below 30%, delay time is not more than 1 s, audio and video calls are smooth. It also shows that the optimization scheme of video coding and decoding based on the VPU hardware characteristics of i.MX6 is feasible and has certain reference value for other similar systems.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.81

【相似文献】