Video communication over bandwidth limited channels is becoming a more and more important service in multimedia communications, so it is necessary to improve the coding efficiency of the video coder while maintaining ...Video communication over bandwidth limited channels is becoming a more and more important service in multimedia communications, so it is necessary to improve the coding efficiency of the video coder while maintaining subjectively acceptable quality. In this paper, we propose a novel method to incorporate the just noticeable distortion(JND) concept into the H.263 coder. We first review the basic concept of JND in the spatial temporal domain, then derive it to the macro block(MB) level to make it usable in the H.263 coder. While producing the same subjective quality, simulation results show that this method can considerably reduce the consumed bits compared with tmn 5 coder without sacrificing the compatibility with the H.263 standard.展开更多
This letter introduces the implementation of H.263 video codec based on multimedia DSP TM1300, and discuses several key problems related to video coding.
视频压缩算法在向DSP(digital signal processing)平台上移植时,大多存在程序结构设计不合理、数据结构冗余等问题,因而会导致缓存命中率下降、DSP的利用率降低.针对这些问题,通过对cache miss、指令跳转等降低DSP效率的不利因素的分析,...视频压缩算法在向DSP(digital signal processing)平台上移植时,大多存在程序结构设计不合理、数据结构冗余等问题,因而会导致缓存命中率下降、DSP的利用率降低.针对这些问题,通过对cache miss、指令跳转等降低DSP效率的不利因素的分析,在H.263的DCT、量化、预测等模块采取重新定义数据结构、改进算法、优化专用指令等一系列措施提高缓存命中率,减少跳转指令,以提高DSP的有效利用率,使得优化后的H.263编码器在保持较高清晰度的情况下,可以对通用中间格式(CIF)的视频序列进行实时处理.展开更多
文摘Video communication over bandwidth limited channels is becoming a more and more important service in multimedia communications, so it is necessary to improve the coding efficiency of the video coder while maintaining subjectively acceptable quality. In this paper, we propose a novel method to incorporate the just noticeable distortion(JND) concept into the H.263 coder. We first review the basic concept of JND in the spatial temporal domain, then derive it to the macro block(MB) level to make it usable in the H.263 coder. While producing the same subjective quality, simulation results show that this method can considerably reduce the consumed bits compared with tmn 5 coder without sacrificing the compatibility with the H.263 standard.
文摘This letter introduces the implementation of H.263 video codec based on multimedia DSP TM1300, and discuses several key problems related to video coding.
文摘视频压缩算法在向DSP(digital signal processing)平台上移植时,大多存在程序结构设计不合理、数据结构冗余等问题,因而会导致缓存命中率下降、DSP的利用率降低.针对这些问题,通过对cache miss、指令跳转等降低DSP效率的不利因素的分析,在H.263的DCT、量化、预测等模块采取重新定义数据结构、改进算法、优化专用指令等一系列措施提高缓存命中率,减少跳转指令,以提高DSP的有效利用率,使得优化后的H.263编码器在保持较高清晰度的情况下,可以对通用中间格式(CIF)的视频序列进行实时处理.
