Research Of Multi-screen Interactive Technology In TV Based On Google Cast

Under the background of intelligence, the function of mobile phones, computers and TV become more and more diversified. How to take advantage of a variety of smart terminals, to achieve interconnection and sharing of resources between the smart terminals, is becoming the object of future development of home entertainment. Multi-screen interactive technology appeared in such a demand-driven and then developed, and quickly became the focus of SARFT, television manufacturers, Internet operators and communication industry. Multi-screen interactive technology has also become the key technology of the future of home entertainment industry. Currently, there are several major multi-screen interactive technology in the market, such as DLNA, Miracast, AirPlay, Google Cast and so on. At Current stage, the problem of multi-screen interactive technology is that specifications are not unified, self-contained between manufacturers, products are not compatible between different manufacturers.This problem cause difficulty to interact with different mobile terminals.From the viewpoint of TV manufacturers and according to the applied situation of multi-screen interactive technology, TV manufacturers should be compatible with a variety of different specifications to improve the ability to adapt to the market. Google Cast technology is an important member of multi-screen interactive technology, and Google is also supporting and promoting Google Cast technology. So it is essential to do research of the integration and application of Google Cast technology in television.Although Google provides the Google Cast SDK for mobile terminal application developers, but Google did not open Google Cast technology, and also did not provide technical support for the TV applications developer. At the side of the TV, can only use Google’s own products (such as Chromecast, Nexus Player, etc.). In order to integrate Google Cast technology in TV product, need to explore and research the communication protocols and the implementation mechanism of Google Cast technology. The purpose of this thesis is to study and analysis the implementation mechanism of Google Cast technology, and achieve self-development program to verify the implementation mechanism of Google Cast technology, then provide theoretical support and technical guidance for the integration of Google Cast technology in TV product. The research content and research results of this thesis are as follows:Firstly, the paper introduces the background of the research and the application situation of multi-screen interactive areas. And Comparatively introduces several mainstream multi-screen interactive technology, such as DLNA, Miracast, AirPlay, Google Cast and so on, then introduces the functions they support, the protocols used and their advantages and disadvantages.Secondly, in current situation, Google Cast technology is not open. This thesis resolves the principle and mechanism of Google Cast technology, and combines own understanding of Google Cast technology, and provide the protocol framework figures of it. By using the Google Cast multi-screen interactive function between Google Nexus 9 tablet and Nexus Player box, and combined with the analysis of wireshark packet capture. Google Cast technology exist two generations, and quite different. In order to distinguish these two generations technology, this thesis name them Google CastV1 and Google CastV2 respectively. Google CastV1 technology can be divided into three parts:discovery of devices, control of receiving application, control of media play. Involving DIAL, RAMP, SSDP, HTTP, WebSocket and other protocols; Google CastV2 technology can be divided into two parts:discovery of devices and communication with device. Involving RAMP, mDNS, TLS, protocol buffer, HTTP, WebSocket and other protocols. This thesis combines own understanding of Google CastV1 technology and Google CastV2 technology, and provide the protocol framework figures of them respectively.Finally, This thesis combines own understanding of implementation mechanism of Google Cast technology, and developed two programs. One is Google CastV1 receiver application, the other is Google CastV2 receiver device discovery module program. This thesis provide the overall structure, program flow, part of the source code, and test results of the two programs. These two programs on the one hand can verify the implementation mechanism of Google Cast technology, on the other hand can provide technical guidance for the integration of Google Cast technology in TV product.