| At present, China is undergoing the transition of transformation of society and economic construction, the process of urbanization, industrialization and internationalization is speeding up sharply, various types of mass incidents are also increasing every day. At the same time, internal security situation has become increasingly serious, crimes skills appear diversified trend, and new cases of high-tech skills appear constantly, which has brought new challenges to the police. Video evidence is getting the welcome of the police for its objectivity, intuitive and correlation characteristics. It is seemd as the most preferred form of evidence, especially dealing with major cases and complex cases for the police.At present, the existing video forensics tools of Hangzhou police can’t meet the requirement of practical work. At the same time, with the improvement of the judicial system in China, the requirements for the data security and authenticity of evidence have also been improved step by step. The ways of the existing video forensics have no the corresponding evidence management functions, which may result in the damage and loss of video evidence, even the illegal modification and replacement.This paper have developed a video forensics system according to the actual demand for Hangzhou police to video forensics business, which can satisfy the multiple scenarios. This system is based on the Android smart phone for the front-end acquisition, with the application client of network broadcast based on B/S architecture and video-on-demand platform. This system uses mobile phone as a video collection, which solves the problem of the rapid response and concealment. It uses 3G communication technology as the transmission medium, which solves the problem of more launching using and application mode diversification; it uses the way with centralized storage and audit export, which solves the problem of the security and authenticity of evidences. Meanwhile, in the realization of video evidence collection, transmission, storage and application and a series of functions, it can realize the application of video broadcast function according to the needs of real work, which solves the problem of the command decision-making which has plagued the police for a long time.In this paper, the research work for police video forensics system based on the Android mobile phone is listed as below:1. To study the related work of video forensics, to summarize the actual evidence collection scene, and to put forward the business requirements. This paper firstly studied the characteristics and defects of the current work of evidence collection by video by police and summed up seven actual work scenes in total of evidence collection by video, which are, case of evidence collection on site, evidence collection in the process of law enforcement, secret evidence collection, command of large case, control of mass incident, dispatch of fighting against risk and disaster relief, and put forward the detailed requirements of evidence collection by video.2. To design system of evidence collection by video, based on Android phone. This paper has used the collection, transmission, storage and application of video evidence site as the thread to design a set of system of evidence collection by video, based on Android, which is divided into two parts of mobile collection terminal and business application terminal.3. To realize mobile collection terminal and business application terminal of system of evidence collection by video based on Android phone. The evidence collection by video applied in the mobile terminal has been achieved, and the X264 encoder is transplanted to do H.264 coding, using RTP/UDP protocol for subcontract. In the business application terminal application platform of video evidence based on the RED5 video server has been realized.4. To complete test work of system of evidence collection by video based on Android phone. This paper adopted the compatibility test of phone collection terminal, delay test of video broadcast and test of reverberation quality to inspect the system, for the intended use. At the same time, the results of reverberation quality test have provided valuable experiences for choosing the appropriate network type in the actual application of system. |
