AV2 is the successor to the AV1 royalty-free video coding standard developed by the Alliance for Open Media (AOMedia). Its primary objective is to deliver substantial compression gains and subjective quality improvements while maintaining low-complexity encoder and decoder operations. This paper describes the transform, quantization and entropy coding design in AV2, including redesigned transform kernels and data-driven transforms, expanded transform partitioning, and a mode & coefficient dependent transform signaling. AV2 introduces several new coding tools including Intra/Inter Secondary Transforms (IST), Trellis Coded Quantization (TCQ), Adaptive Transform Coding (ATC), Probability Adaptation Rate Adjustment (PARA), Forward Skip Coding (FSC), Cross Chroma Component Transforms (CCTX), Parity Hiding (PH) tools and improved lossless coding. These advances enable AV2 to deliver the highest quality video experience for video applications at a significantly reduced bitrate.

翻译：AV2是由开放媒体联盟（AOMedia）开发的AV1免版税视频编码标准的后继者。其主要目标是在保持低复杂度编码器与解码器操作的同时，实现显著的压缩增益与主观质量提升。本文阐述了AV2中的变换、量化与熵编码设计方案，包括重新设计的变换核与数据驱动变换、扩展的变换分区模式，以及依赖于模式与系数的变换信号表示机制。AV2引入了多项新型编码工具：帧内/帧间次级变换（IST）、网格编码量化（TCQ）、自适应变换编码（ATC）、概率自适应速率调整（PARA）、前向跳跃编码（FSC）、跨色度分量变换（CCTX）、奇偶隐藏（PH）工具以及改进的无损编码技术。这些进展使AV2能够以显著降低的码率为视频应用提供最高质量的视觉体验。