Searching Priors Makes Text-to-Video Synthesis Better
Haoran Cheng, Liang Peng, Linxuan Xia, Yuepeng Hu, Hengjia Li, Qinglin Lu, Xiaofei He, Boxi Wu
TL;DR
This paper tackles the realism gap in text-to-video synthesis by shifting from large-scale model training to a two-stage search-based approach that leverages motion priors from real videos. It introduces a video retrieval module that semantically matches prompts to existing text-video pairs, followed by motion extraction, distillation, and fine-tuning of a pre-trained T2V model using the retrieved priors. The method employs two forms of text representation (sentence-level and atomized semantics) and a two-stage matching (coarse filtering and ranking) to select the most relevant reference; keyframes are extracted and grounded to distill motion via a cosine-alignment objective, culminating in final video synthesis from the prompt. Empirical results on a single RTX 4090 show improved temporal coherence and motion realism versus state-of-the-art baselines, with user studies supporting higher perceived quality, while the authors acknowledge retrieval and keyframe extraction limitations and propose future refinements.
Abstract
Significant advancements in video diffusion models have brought substantial progress to the field of text-to-video (T2V) synthesis. However, existing T2V synthesis model struggle to accurately generate complex motion dynamics, leading to a reduction in video realism. One possible solution is to collect massive data and train the model on it, but this would be extremely expensive. To alleviate this problem, in this paper, we reformulate the typical T2V generation process as a search-based generation pipeline. Instead of scaling up the model training, we employ existing videos as the motion prior database. Specifically, we divide T2V generation process into two steps: (i) For a given prompt input, we search existing text-video datasets to find videos with text labels that closely match the prompt motions. We propose a tailored search algorithm that emphasizes object motion features. (ii) Retrieved videos are processed and distilled into motion priors to fine-tune a pre-trained base T2V model, followed by generating desired videos using input prompt. By utilizing the priors gleaned from the searched videos, we enhance the realism of the generated videos' motion. All operations can be finished on a single NVIDIA RTX 4090 GPU. We validate our method against state-of-the-art T2V models across diverse prompt inputs. The code will be public.
