Recent multimodal large language models (MLLMs) have shown promising performance on video quality assessment (VQA) tasks. However, adapting them to new scenarios remains expensive due to large-scale retraining and costly mean opinion score (MOS) annotations. In this paper, we argue that a pretrained MLLM already provides a useful perceptual prior for VQA, and that the main challenge is to efficiently calibrate this prior to the target MOS space. Based on this insight, we propose DPC-VQA, a decoupling perception and calibration framework for video quality assessment. Specifically, DPC-VQA uses a frozen MLLM to provide a base quality estimate and perceptual prior, and employs a lightweight calibration branch to predict a residual correction for target-scenario adaptation. This design avoids costly end-to-end retraining while maintaining reliable performance with lower training and data costs. Extensive experiments on both user-generated content (UGC) and AI-generated content (AIGC) benchmarks show that DPC-VQA achieves competitive performance against representative baselines, while using less than 2% of the trainable parameters of conventional MLLM-based VQA methods and remaining effective with only 20% of MOS labels. The code will be released upon publication.
Figures & tables
Figure 1. Comparison between existing MLLM-based VQA pipelines and the proposed DPC-VQA framework. Top left: existing methods typically predict quality scores by training or fine-tuning an MLLM with a regressor. Bottom left: when the target scenario changes, they often require scenario-specific retraining with costly MOS supervision. Right: DPC-VQA instead preserves the pretrained MLLM as a frozen quality prior and adapts it through lightweight residual calibration.
Figure 2. Motivation for decoupling quality perception and residual calibration. (a) Frozen MLLM quality predictions are already correlated with MOS, indicating a useful base quality prior. (b) The residual error shows a clear dependency on the base score, suggesting that the remaining discrepancy is structured and learnable. (c) Residual errors are concentrated around zero, implying that most samples require only limited correction. These results motivate calibrating a perceptually grounded base score rather than relearning video quality prediction end-to-end. All results are computed on the KoNViD-1k dataset for analysis.
Figure 3. Overview of the proposed DPC-VQA framework. A frozen MLLM first produces a base quality estimate and perceptual representations as a quality prior. A lightweight base-aware residual calibration branch then predicts token-wise corrections conditioned on the base estimate and aggregates them into a residual adjustment. The final quality score is obtained by combining the base estimate with the aggregated residual, enabling efficient adaptation under limited MOS supervision.
Methods
KoNViD-1k
YouTube-UGC
LIVE-VQC
T2VQA
Human-AGVQA
SRCC
PLCC
SRCC
PLCC
SRCC
PLCC
SRCC
PLCC
SRCC
PLCC
supervised
BRISQUE (TIP, 2012) ( Mittal et al., 2012 )
0.634
0.615
0.472
0.447
0.459
0.451
0.505
0.507
0.438
0.446
TLVQM (TIP, 2019) ( Korhonen, 2019 )
0.773
0.769
0.669
0.659
0.658
0.639
0.610
0.613
0.582
0.584
VSFA (ACMMM, 2019) ( Li et al., 2019 )
0.794
0.799
0.787
0.789
0.718
0.771
0.704
0.708
0.618
0.633
RAPIQUE (OJSP, 2021) ( Tu et al., 2021 )
0.811
0.819
0.774
0.781
0.740
0.764
0.682
0.703
0.632
0.648
Table 1. Comparison with representative supervised and few-shot methods on five VQA benchmarks spanning both UGC and AIGC scenarios. Methods marked with ∗ are designed for AIGC-VQA and are therefore reported only on AIGC benchmarks.
Method
KoNViD-1k
YouTube-UGC
SRCC
PLCC
SRCC
PLCC
Base only ( y^=qb )
0.774
0.786
0.760
0.753
Direct regression
0.836
0.844
0.821
0.818
Score-conditioned regression
0.868
0.876
0.849
0.855
Residual calibration (ours)
0.883
0.891
0.868
0.871
Table 2. Comparison between residual calibration and direct regression on KoNViD-1k and YouTube-UGC.
Inputs
KoNViD-1k
YouTube-UGC
SRCC
PLCC
SRCC
PLCC
HvisL only
0.834
0.842
0.814
0.820
Haux only
0.809
0.817
0.787
0.794
HvisL+Haux
0.854
0.862
0.836
0.841
HvisL+Haux+qb
0.875
0.883
0.858
0.862
HvisL+Haux+qb+ub
0.883
0.891
0.868
0.871
Table 3. Ablation on different information sources used for calibration on KoNViD-1k and YouTube-UGC.
Aggregation strategy
KoNViD-1k
YouTube-UGC
SRCC
PLCC
SRCC
PLCC
Mean pooling
0.859
0.867
0.842
0.847
Self-attention aggregation
0.874
0.882
0.859
0.865
Calibration queries (ours)
0.883
0.891
0.868
0.871
Table 4. Ablation on different evidence aggregation strategies on KoNViD-1k and YouTube-UGC.
M
KoNViD-1k
YouTube-UGC
SRCC
PLCC
SRCC
PLCC
1
0.861
0.869
0.846
0.850
4
0.874
0.882
0.858
0.863
8
0.883
0.891
0.868
0.871
16
0.879
0.887
0.864
0.868
Table 5. Sensitivity analysis on the number of calibration queries M on KoNViD-1k and YouTube-UGC.
λres
KoNViD-1k
YouTube-UGC
SRCC
PLCC
SRCC
PLCC
0
0.869
0.877
0.853
0.857
0.01
0.875
0.881
0.859
0.862
0.05
0.883
0.891
0.868
0.871
0.1
0.880
0.888
0.864
0.868
Table 6. Effect of the residual regularization coefficient λres on KoNViD-1k and YouTube-UGC.
α
KoNViD-1k
YouTube-UGC
SRCC
PLCC
SRCC
PLCC
0.1
0.871
0.879
0.856
0.860
0.2
0.883
0.891
0.868
0.871
0.3
0.876
0.884
0.860
0.865
0.5
0.867
0.875
0.851
0.856
Table 7. Effect of the residual bound α on KoNViD-1k and YouTube-UGC.
Figure 4. Data efficiency comparison under different training ratios on KoNViD-1k and YouTube-UGC.