基于Android平台的视频通信系统研究与实现

发布时间：2018-03-22 07:17

本文选题：H.264编解码　切入点：NAT穿越　出处：《辽宁大学》2017年硕士论文　论文类型：学位论文

【摘要】：现如今,智能移动终端手持设备在不断地占领着市场,改变了人们的通讯交流方式。这个期间,视频通信得到了快速的发展。人们已经不满足于发送文本和语音信息,以视频为主的通信方式更受青睐,对视频通信质量的要求也在增加。所以,在低带宽时提高视频的通信质量即降低传输的码率还是有必要的,这也可以应用在移动网络下的视频聊天,减少带宽产生的费用。本文研究了对处在不同内网中的客户端进行实时视频通信的课题,详细阐述了该系统实现的可行性,以及对所涉及到的相关技术进行了深入的研究和分析,并结合前人的工作,大胆进行创新,提出新的实践思路。在此基础之上,对视频通信系统进行了详细的设计,主要包括音频和视频的采集和编解码,NAT穿越的实现,以及RTP实时传输的设计。在视频传输的过程中,为了降低视频传输过程中的码率,本文采用目前较主流的,且稳定性较高的H.264视频压缩编码算法对视频帧进行压缩,以此减少视频帧间的冗余。对于音频的编码,采用编码效率较好的AAC编码技术,对PCM原始音频数据进行压缩,以减少传输的带宽。由于通信的双方处在不同的内网中,不能直接进行通信,所以需要通过服务器协助双方建立通信连接。本文采用基于TCP的协议实现透传,提高了可靠性,与基于UDP的方式相比,减少了通过服务器中转数据产生的延迟。同时,为了音频和视频能够实时的到达接收端,利用RTP协议技术来实现对音视频的实时传输和同步。在此基础之上,考虑到在最近很热的智能家居研发中,利用智能电视与远方的亲友进行视频聊天时,背景几乎是不变的,通信的双方主要关注的是对方的人脸,而忽略无关的背景。所以,在这种情况下,本文通过利用人脸检测来进一步减少视频的传输码率,改善通信的质量。通过对系统的不断测试和完善,该系统可以实现视频通信的功能,且在网络带宽较低时,通信质量良好。
[Abstract]:Nowadays, smart mobile terminal handheld devices are constantly occupying the market, changing the way people communicate. During this period, video communication has developed rapidly. People are no longer satisfied with sending text and voice messages. Video based communication is more popular, and the requirement of video communication quality is also increasing. Therefore, it is necessary to improve video communication quality in low bandwidth, that is, to reduce the bit rate of transmission. This can also be used in the mobile network video chat, reducing the cost of bandwidth. This paper studies the subject of real-time video communication for clients in different intranets, and expounds the feasibility of the implementation of the system in detail. And the related technology involved in the in-depth research and analysis, and combined with previous work, bold innovation, put forward a new practical thinking. On the basis of this, the video communication system is designed in detail. It mainly includes the realization of audio and video acquisition and encoding and decoding, and the design of RTP real-time transmission. In the process of video transmission, in order to reduce the bit rate in the process of video transmission, this paper adopts the current mainstream, The stable H.264 video compression algorithm can reduce the redundancy between the video frames. For the audio coding, the AAC coding technology with good coding efficiency is used to compress the original PCM audio data. In order to reduce the bandwidth of transmission. Because the two sides of the communication are in different intranet, they can not communicate directly, so it is necessary to assist the two sides to establish communication connection through the server. In this paper, the protocol based on TCP is used to realize the transparent transmission, which improves the reliability. Compared with the UDP based approach, it reduces the latency generated by transferring data through the server. At the same time, in order for audio and video to reach the receiving end in real time, Using RTP protocol technology to realize the real-time transmission and synchronization of audio and video. On this basis, considering that in the recent research and development of smart home, the background is almost unchanged when using smart TV to chat with friends and relatives in the distance. The two sides of the communication are mainly concerned with the face of the other party, while ignoring the irrelevant background. Therefore, in this case, we use face detection to further reduce the transmission rate of the video. The system can realize the function of video communication by continuously testing and perfecting the system, and the communication quality is good when the network bandwidth is low.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP316;TN919.8

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