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AI図鑑

動画理解

動画の中で何が起きたかを理解する

動画中級 #25
入力動画テキストテキスト

本ページの本文は英語で提供されています。タイトルと導入は日本語化されています。

この能力とは何か

Takes a video, optionally with a question, and outputs a description or answer about content, events and timeline — what happened after three minutes, or whether a movement was performed correctly. It adds a time dimension to image understanding and must distinguish events with similar frames but different order. Input is usually sampled into frames and compressed before entering the model.

技術的にどう実現するか

Frames are sampled on a fixed or adaptive schedule, a vision encoder turns each into tokens, and frame order with timestamps enters a multimodal Transformer whose language side produces text. Long videos are managed with hierarchical summarisation, keyframe selection or memory mechanisms to cap the token budget. Precise localisation is handled by a dedicated temporal grounding head or by having the model output a time interval.

代表的な製品

5

関連する組織

代表的な用途

  • Event search in surveillance and security footage
  • Technique review in sport and fitness
  • Overviews of lectures and meetings
  • Moderation and locating offending segments

どう評価するか

Video QA accuracy
Share answered correctly on annotated questions
Temporal grounding mIoU
Mean IoU between predicted and true time intervals
Video captioning CIDEr
Semantic match of captions against references

限界と難しさ

  • Frame sampling discards mid-video detail, and one-off events are the easiest to miss
  • Fine temporal ordering — who did what first — is vague and often reversed
  • Judgement is unstable when audio and picture conflict, as dubbed audio can make the model waver

背景にある概念