基于DirectShow的DVB-T数字电视中EPG解码

EPG decoder in DVB-T based on DirectShow

DVB-T数字电视标准是一种比较成熟的数字电视标准,不仅在欧洲得到广泛的应用,在国内多个地区的实验网也采用DVB-T标准。DVB-T提供了比较完善的电子节目指南EPG(Electronic Program Guide)功能,EPG提供当前播放的节目和即将播放节目的相关信息,可以实现对节目的快速检索和访问。由于EPG包含在DVB-T的SI信息中,因此详细分析了从SI信息表中提取EPG的过程。而Windows平台上的数字电视接收是以DirectShow技术为基础的,所以EPG的解码程序也应该成为DirectShow链路结构的一部分。针对传统的EPG解码DirectShow链路结构的缺陷,提出了一种音视频数据与SI数据分离的DirectShow链路结构,把EPG解码程序封装成独立的Filter。实验表明,提出的方法能够有效地对EPG数据进行解码,在牺牲一部分CPU时间的基础上,数据的完整性得到了明显提高。

DVB-T is a mature digital television standard,and is widely used in Europe,also is used in China by several experimental digital television networks.DVB-T provides complete Electronic Program Guide （EPG） function,which gives relevant information about current program and next program,and customers can use EPG to fast get and retrieve program information.As EPG is included in SI information,so this paper presents how to decode EPG from SI tables.Because the digital TV receiver on Windows platform is based on Directshow technology,so EPG decoder function should also be a part of Directshow filter chains.Traditional EPG decoder filter chains have structural deficiencies,and this paper gives a completely revised EPG decoder filter chains,which departs A/V data and SI data from TS stream.Experiments show that this filter chain can more efficiently and completely decodes EPG data in terms of slightly CPU time raising.