Research On FPGA-based Digital Television Transport Stream Subtitle Insertion Technology

This paper presents the design and implementation of digital television transport stream subtitle insertion system, which is one of the new equipments in the television broadcasting system when the system changes from analog to digital. In order to fit the digital television network, the design which is based on the FPGA is proposed to solve the issue. Compared to the methods based-on software composite, the FPGA-based design can work more stably and save the energy.The main work in this paper: Firstly, the paper presents the design of the digital television transport stream subtitle insertion system which is base on the characteristics of digital television transport stream. Then some issues are solved in the implementation, including abnormal detection and treatment of the transport stream, the data transport stream multiplexing, transport stream rate control, and the transport stream PCR correction. These parts is achieved by using Verilog language implementation in FPGA, also the modules in the design are given in this paper, as well as the flowchart and the key code. At last the effects are shown from the FPGA hardware platform between the transport stream before and after the correction.The main achievement of this paper: Firstly, we analyze the reasons of the abnormal transport stream, then some solutions are made in order to solve the issues which bright by the abnormal transport stream, we can ensure that the system will detect the unusual situation and reset automatically and will not cause a system crash. Secondly, we find that the PCR intervals are not fit the standard in the multiplexing, the method that dynamic adjustment of multiplexed data schedule by using of the relevant transport stream bit rate results is proposed, and it solves the PCR interval abnormal problem in the transport stream multiplexing system effectively.