Vid2Seq
Google's single-stage dense video captioner: special time tokens let one model emit event boundaries and captions as a single sequence, pretrained on millions of narrated YouTube videos — the CVPR 2023 approach the field still builds on.
About
Vid2Seq (CVPR 2023, arXiv 2302.14115) from Google Research with Inria reframed dense video captioning. Instead of separate proposal and captioning stages, it augments a language model with special time tokens, so the model generates event boundaries and their textual descriptions in one output sequence. The key enabler is scale without annotation cost: pretraining reformulates transcribed-speech sentence boundaries from narrated videos as pseudo event boundaries, using the YT-Temporal-1B collection of millions of narrated videos, with generative plus denoising objectives. The resulting model set the state of the art on ActivityNet-Captions, YouCook2 and ViTT dense-captioning benchmarks at publication (author-reported), and also generalized to video paragraph captioning and few-shot settings. Code is Apache 2.0 in google-research/scenic; the README initially said checkpoints were coming, and later work confirms a public pretrained checkpoint exists and is reused by follow-up research. No hosted API.
Specs
Context window
Pricing
Free quota
API access
Weights
Released
Benchmarks
- State of the art on ActivityNet-Captions, YouCook2 and ViTT dense event captioning at publication (author-reported)\n- Generalized to video paragraph captioning and few-shot settings (author-reported)\n- A later paper (Streaming Dense Video Captioning) confirms using the publicly released pretrained checkpoint\n- All original figures author-reported; the field has since moved to LLM-based captioners
Provider-reported unless a source says otherwise. Benchmarks are marketing-adjacent by nature — treat them as directional.
Use cases
Trust score — 8/10
Scored 8/10 (TIER verified, metrics-v1). Evidence: peer-reviewed at CVPR 2023; Apache 2.0 code in the maintained Scenic repo; the time-token idea became foundational and the public checkpoint is still reused by later research. Strengths: a landmark reframing of dense captioning with an elegant weak-supervision trick (narrated video as free labels). Docked for: (1) benchmark figures are author-reported and from 2023, before LLM-based captioners took over; (2) the checkpoint release was delayed and poorly documented, though later confirmed public. License: Apache 2.0.
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 8.0/10
- Maintenance · recency, releases, issue load
- 7.0/10
- Openness · license + docs
- 9.0/10
- Manual review · sanity read + red-flag check
- 8.0/10
- · CVPR 2023 landmark: single-stage dense captioning with time tokens, pretrained on YT-Temporal-1B narrated videos.
- · SOTA on ActivityNet-Captions, YouCook2, ViTT at publication (author-reported).
- · Public checkpoint confirmed in use by later research; maintained inside Google Scenic.