To achieve controllable subjective quality in image coding, this paper proposes a Video Multi-method Assessment Fusion (VMAF)-oriented image coding pre-analysis algorithm, enabling the adaptive derivation of quantization parameters corresponding to a specified quality target. First, a$Q-\mathcal{V}$model is constructed to describe the relationship between encoding quantization and VMAF distortion. Then, a Three-stage Progressive Control (TPC) algorithm, shown in Fig. 1(a), is designed to adapt quantization parameters using the discovered$Q-\mathcal{V}$model. The first two stages, based on lightweight feature extraction, iteratively fit the distortion metrics intrinsically calculated by VMAF to predict the VMAF value for a given sample under specified distortion conditions. The final stage fits the$Q-\mathcal{V}$model parameters using multi-point VMAF distortion data and outputs the corresponding quantization step for encoder control. A two-pass refinement algorithm, depicted in Fig. 1(b), further adjusts the quantization parameters based on the first encoding pass, improving quality control accuracy and framework robustness. Experiments on four datasets show that the quality control error remains below 1.293% for various VMAF targets, and the two-pass refinement reduces it further to 0.710%, outperforming existing methods.

The new coding tools improved the performance for H.266/VVC but also brought challenges for hardware integer motion estimation (IME). First, the data dependency in deriving a predicted motion vector (PMV) is more severe. Second, the overhead of IME is increased by the complex partition mechanism. The challenges are tougher for IME in coding tree unit (CTU) level pipelined encoder. In this paper, we propose a hardware-friendly CTU-level IME algorithm with three innovative designs. First, a PMV prediction is proposed to derive PMVs in advance. Second, all divided blocks are categorized into either binary/quadra tree (BTQT) or ternary tree (TT) blocks. The motion vectors (MVs) of BTQT blocks are estimated with a multi-resolution search. The MVs of TT blocks are inferred from the estimated MVs with an inference algorithm. The proposed algorithm suffers $ 1.20\%$ degradation but reduced the complexity by $ 80\%$ compared to the reference software.