This paper presents an intra coding tool, named Merge mode for Template-based Intra Mode Derivation (TIMD). TIMD-Merge has been adopted in the 15\textsuperscript{th} version of the Enhanced Compression Model (ECM) software that explores video coding technologies beyond Versatile Video Coding (VVC) standard. This proposed tool operates on top of the regular TIMD mode that applies a template-based search on a causal adjacent template at top and at left of the current block, in order to find the best Intra Prediction Modes (IPMs) that matches the template. The proposed TIMD-Merge in this paper addresses a shortcoming in the regular TIMD method where due to texture discrepancy, the adjacent template information around the block is not reliable. To do so, the proposed TIMD-Merge constructs a list of all TIMD-coded blocks in relatively larger template area than the template of the regular TIMD, which also includes non-adjacent neighboring blocks. This list, called the merge list, is then sorted on the template to give one best set of TIMD modes. The use of TIMD-Merge mode is signalled at the block level and the implementation in the ECM-14.0 demonstrates -0.08\% performance improvement in terms of luma BDR gain, with negligible encoding and decoding runtime increase of 100.6% and 100.2%, respectively.

翻译：本文提出了一种帧内编码工具，称为基于模板的帧内模式推导（TIMD）的合并模式。TIMD-合并模式已被纳入增强压缩模型（ECM）软件的第15版中，该软件探索了超越通用视频编码（VVC）标准的视频编码技术。该工具在常规TIMD模式的基础上运行，常规TIMD模式通过对当前块上方和左侧的因果相邻模板进行基于模板的搜索，以找到与模板匹配的最佳帧内预测模式（IPM）。本文提出的TIMD-合并模式解决了常规TIMD方法中的一个缺陷，即由于纹理差异，块周围的相邻模板信息不可靠。为此，所提出的TIMD-合并模式构建了一个包含所有TIMD编码块的列表，该列表使用的模板区域比常规TIMD的模板更大，且包括非相邻的邻近块。此列表称为合并列表，随后根据模板进行排序，以提供一组最佳的TIMD模式。TIMD-合并模式的使用在块级别进行信号指示，在ECM-14.0中的实现表明，其在亮度BDR增益方面实现了-0.08%的性能提升，编码和解码运行时间分别仅增加100.6%和100.2%，可忽略不计。