SAM 3.1 made object tracking twice as fast by stopping the model doing the same work sixteen times. Meta released it on 27 March 2026 as a drop-in replacement for SAM 3, and the whole change is one idea: track many objects in a single pass instead of one pass each.Meta AI, SAM 3.1: Faster and More Accessible Real-Time Video Detection and Tracking, 27 Mar 2026, read at source 16 Sep 2026.
- Drop-in replacement. Meta’s own word for it — no rearchitecting required.
- Up to 16 objects in one forward pass, where each object used to need its own.
- 16 to 32 frames per second on a single H100, on videos with a medium number of objects.
- Cheaper hardware becomes viable, which is the practical point of the release.
- The weights are gated. Hugging Face asks you to accept conditions before downloading.
What changed from SAM 3
Only the video path, and only how it handles more than one object. Meta: “Previously, each object required its own dedicated pass, but with multiplexing, SAM 3.1 processes all tracked objects together, eliminating redundant computation and memory bottlenecks.”
The number attached to that: the model can “track up to 16 objects in a single forward pass”, which “doubles the processing speed for videos with a medium number of objects, increasing throughput from 16 to 32 frames per second on a single H100 GPU”.Meta AI, SAM 3.1, 27 Mar 2026, read at source 16 Sep 2026.
Meta also claims it helps in crowded scenes rather than just going faster: the approach “streamlines performance and enhances accuracy in crowded scenes”.
This is an efficiency release, not a capability release. What SAM 3.1 can recognise is what SAM 3 could recognise — it just stops paying for the same computation once per object.
What SAM 3 is, if you missed it
A segmentation model you can prompt with words. Meta describes it as “a unified model for detection, segmentation, and tracking of objects in images and video using text, exemplar, and visual prompts”. The model card puts the scale of the vocabulary bluntly: it handles “over 50x more unique concepts than existing benchmarks”.Meta, facebook/sam3.1 model card, read at source 16 Sep 2026: SAM 3 “detects, segments, and tracks objects using text or visual prompts such as points, boxes, and masks”.
In plain terms: you type a short noun phrase and it finds every instance of that thing, in a still or across a clip.
Where you have already seen it
Meta names the products. SAM 3 and SAM 3D “are being used to enable the new View in Room feature on Facebook Marketplace”; new effects are planned for the Edits app, where “Creators can apply dynamic effects to people or objects in their videos — simplifying a complex editing workflow to just one tap”; and Meta says new creation experiences “will be coming to Vibes on the Meta AI app and meta.ai on the web, where people can use AI visual creation tools and remix existing AI-generated videos”.
Two of those three are future tense in Meta’s own sentence. This page has not checked whether the Edits effects or the Vibes features shipped.
Getting hold of it
| Artefact | Where |
|---|---|
| Model checkpoint | Hugging Face, behind an access gate |
| Code | the SAM 3 GitHub repository |
| Research paper | linked from the announcement |
| Try it without installing | Segment Anything Playground |
Meta, facebook/sam3.1, read at source 16 Sep 2026: the page says “Log in or Sign Up to review the conditions and access this model content”, and that “This repository hosts only the SAM 3.1 model checkpoints — there is no Hugging Face Transformers integration.”
That second sentence matters if you assumed a one-line load. Meta points you at the GitHub repository “for installation, code, usage examples, and full documentation”.
What this page could not verify
- The speed claim. Meta’s figure, on Meta’s hardware, not reproduced here.
- The accuracy claim in crowded scenes. Stated in the announcement without a benchmark in the text.
- Whether the Edits and Vibes features shipped. Announced as coming.
- What the access conditions say. The gate requires an account this site did not use.
Meta AI, SAM 3.1: Faster and More Accessible Real-Time Video Detection and Tracking With Multiplexing and Global Reasoning, 27 March 2026 · Meta, facebook/sam3.1 model card. Both read at source on 16 September 2026.
Performance figures are the vendor’s.