An Advanced Hierarchical Motion Estimation Scheme With Lossless Frame Recompression and Early-Level Termination for Beyond High-Definition Video Coding
An Advanced Hierarchical Motion Estimation Scheme With Lossless Frame Recompression and Early-Level Termination for Beyond High-Definition Video Coding
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DOI：
10.1109/tmm.2011.2171677
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发表时间：
2012-04
影响因子：
7.3
通讯作者：
Xuena Bao;Dajiang Zhou;Peilin Liu;S. Goto
中科院分区：
文献类型：
--
作者：
Xuena Bao;Dajiang Zhou;Peilin Liu;S. Goto
本文提出了一种基于无损帧重压缩和早期终止策略的高硬件效率快速算法，用于超高清视频编码器的大搜索范围运动估计。为了实现高质量的分层运动搜索，我们提出了一种先进的分层运动搜索方案，该方案通过高效的细化阶段处理多分辨率运动搜索。这使得数据和硬件的高重用能够以更低的带宽和内存成本实现，同时实现比以前的工作更高的ME质量。在此基础上提出了一种无损帧重压缩方案，进一步降低了带宽。为了满足分层运动搜索结构的随机访问约束，采用了分层存储组织和分层两步数据获取策略。同时，提出了一种允许低电平参考高电平进行压缩的调平压缩策略，以有效地减少带宽。此外，还采用了一种适用于分层ME结构的早期终止方法。该方法通过建立基于当前块模式和运动搜索级别的阈值来终止高水平冗余运动搜索；它还应用了早期精化终止，以避免对高层进行不必要的精化。实验结果表明，与以往的方案相比，该方案的比特率增长率要低得多，特别是对于高运动序列，同时在SR为[-128,127]的情况下，节省了相当大的内存和带宽成本。
In this paper, we present a hardware-efficient fast algorithm with a lossless frame recompression scheme and early-level termination strategy for large search range (SR) motion estimation (ME) utilized in beyond high-definition video encoder. To achieve high ME quality for hierarchical motion search, we propose an advanced hierarchical ME scheme which processes the multiresolution motion search with an efficient refining stage. This enables high data and hardware reuse for much lower bandwidth and memory cost, while achieving higher ME quality than previous works. In addition, a lossless frame recompression scheme based on this ME algorithm is presented to further reduce bandwidth. A hierarchical memory organization as well as a leveling two-step data fetching strategy is applied to meet constraint of random access for hierarchical motion search structure. Also, the leveling compression strategy by allowing a lower level to refer to a higher one for compression is proposed to efficiently reduce the bandwidth. Furthermore, an early-level termination method suitable for hierarchical ME structure is also applied. This method terminates high-level redundant motion searches by establishing thresholds based on current block mode and motion search level; it also applies the early refinement termination in order to avoid unnecessary refinement for high levels. Experimental results show that the total scheme has a much lower bit rate increasing compared with previous works especially for high motion sequences, while achieving a considerable saving of memory and bandwidth cost for large SR of [-128,127].