摘要： 针对宽带IPTV视频源向移动网络和移动终端提供视频服务需要解决的视频转码问题，设计开发以软件方式实现的实时视频转码系统，可将MPEG-4格式的高码率、高分辨率节目源实时转换为适合移动网络和移动终端的低码率、低分辨率视频。在误差补偿转码框架的基础上，提出一种自适应的转码时延保证方法，解决了转码计算复杂性和转码质量均衡的关键技术问题，保证了转码系统的实时性。测试结果表明，实现的转码系统视频转换质量损失少、实时性高。

关键词: 移动网络, 实时视频转码, 降码率, 降分辨率, 时延保证

Abstract: Video transcoding is emerging as a key technology to provide video streaming service for mobile devices on wireless networks when using video sources from broadband IPTV. This paper designs and develops a software implemented real-time video transcoding system which can convert high bit-rate, high resolution MPEG-4 video sources to low bit-rate, low resolution video in real-time to support video streaming over mobile networks. An adaptive transcoding scheme with delay guarantee is proposed in the paper based on the well-known drift compensation transcoding architecture. This scheme not only leverages the computation complexity and video quality but also ensures the extra delay caused by transcoding process. Experimental results illustrates that the system can achieve real-time transcoding with little quality degradation.

Key words: mobile networks, real-time video transcoding, bitrate reduction, resolution reduction, delay-guarantee

中图分类号: 

• TP391