针对数字信号处理器的片上存取结构特点,提出了一个优化视频解码运动补偿过程数据布局的方案。在片上便签式存储器(SPM)中设置一个乒乓缓冲存储区用于保存运动补偿所需的数据。在对当前宏块进行运动补偿的同时,预取后续运动补偿所需的数据替换其中不再使用的数据;同时,通过数据索引算法获得运动补偿所需的数据的地址,从而实现数据处理与数据存取的并行流水优化。基于TMS320DM642处理器的实验结果表明,优化后MPEG-4视频解码器的解码速度平均提高了6.7%,整个解码过程中DM642的片上二级缓存的能耗平均降低了18.5%。由此可见,对运动补偿过程进行数据布局优化确实可以提高解码性能并降低能耗。
According to the digital signal processor (DSP) chip access structure characteristics, put forward an optimization video decoding motion compensation process data layout scheme. A memory structure of ping-pang buffer is set in Scratch Pad Memory (SPM) for prefetching the data for motion compensation. In the current macro block motion compensation at the same time, prefetch subsequent motion compensation required data replace one no longer use data. In addition, an index algorithm is used to get the address of data for motion compensation, so as to realize data processing and data access parallel flow optimization. The experiments are carded out on a TMS320DM642 platform for a MPEG-4 video decoder. It achieves an increase of about 6.7% in decoding speed and an energy consumption reduction of 18.5% on average for the DM642 level 2 on-chip memory after the optimization. This indicates that the optimization of data layout for motion compensation could enhance the performance and reduce the energy consumption.