The HEVC test model (HM) still belongs to block-based hybrid video coding framework, except that the macroblock is extended to larger size (up to 64×64) compared with H.264/AVC. In order to facilitate syntax representation of block hierarchy, three block concepts are introduced: coding unit (CU), prediction unit (PU), and transform unit (TU). The overall coding structure is characterized by the various sizes of CU, PU and TU in a recursive manner, once the size of largest coding unit (LCU) and the hierarchical depth of CU are defined.
CU, the basic coding unit like the macroblock and sub-macroblock in H.264/AVC, can have various sizes but is restricted to be a square shape. Given the size and hierarchical depth of LCU, CU can be expressed in a recursive quadtree representation adapted to the picture. Figure 1 (b) shows maximum possible recursive CU structure in HM (LCU size = 64 and hierarchical depth = 4). In HM, the coding unit tree structure is limited from 8×8 to 64×[......]

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Permanent Link: Analysis of Coding Tools in HEVC Test Model (HM 1.0) – Coding Structure

The HEVC test model (HM) was formally established in the 3rd JCT-VC meeting in Guangzhou, China. HM only contains the minimum set of well tested tools together from a coherent design that is confirmed to show good capability, meanwhile it also follows the “one tool one functionality“ approach. It expects to closely resemble the performance of best–performing proposals, as TMuC did, and plans to contain different clusters of tools (could become a seed for profile in future) with as much commonality as possible. Currently, two configurations of typical coding tools are suggested: High Efficiency and Low Complexity, as listed in the following table.
Table 1. Structure of tools forming the high efficiency and low complexity configurations of the HM

High Efficiency
Low Complexity

Coding unit tree structure (8×8 up to 64×64 luma samples)

Prediction units

Transform unit tree structure (maximum of 3 levels)
Transform unit tree structure (maximum of 2 levels)

Transform bloc[......]

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Permanent Link: Analysis of Coding Tools in HEVC Test Model (HM 1.0) – Overview