MM-Narrator: Narrating Long-form Videos with Multimodal In-Context Learning

We present MM-Narrator a novel system leveraging GPT-4 with multimodal in-context learning for the generation of audio descriptions (AD). Unlike previous methods that primarily focused on downstream fine-tuning with short video clips MM-Narrator excels in generating precise audio descriptions for videos of extensive lengths even beyond hours in an autoregressive manner. This capability is made possible by the proposed memory-augmented generation process which effectively utilizes both the short-term textual context and long-term visual memory through an efficient register-and-recall mechanism. These contextual memories compile pertinent past information including storylines and character identities ensuring an accurate tracking and depicting of story-coherent and character-centric audio descriptions. Maintaining the training-free design of MM-Narrator we further propose a complexity-based demonstration selection strategy to largely enhance its multi-step reasoning capability via few-shot multimodal in-context learning (MM-ICL). Experimental results on MAD-eval dataset demonstrate that MM-Narrator consistently outperforms both the existing fine-tuning-based approaches and LLM-based approaches in most scenarios as measured by standard evaluation metrics. Additionally we introduce the first segment-based evaluator for recurrent text generation. Empowered by GPT-4 this evaluator comprehensively reasons and marks AD generation performance in various extendable dimensions.