  Contrastive Language-Image Pre-training (CLIP) is an approach that has
advanced research and applications in computer vision, fueling modern
recognition systems and generative models. We believe that the main ingredient
to the success of CLIP is its data and not the model architecture or
pre-training objective. However, CLIP only provides very limited information
about its data and how it has been collected, leading to works that aim to
reproduce CLIP's data by filtering with its model parameters. In this work, we
intend to reveal CLIP's data curation approach and in our pursuit of making it
open to the community introduce Metadata-Curated Language-Image Pre-training
(MetaCLIP). MetaCLIP takes a raw data pool and metadata (derived from CLIP's
concepts) and yields a balanced subset over the metadata distribution. Our
experimental study rigorously isolates the model and training settings,
concentrating solely on data. MetaCLIP applied to CommonCrawl with 400M
image-text data pairs outperforms CLIP's data on multiple standard benchmarks.
In zero-shot ImageNet classification, MetaCLIP achieves 70.8% accuracy,
surpassing CLIP's 68.3% on ViT-B models. Scaling to 1B data, while maintaining
the same training budget, attains 72.4%. Our observations hold across various
model sizes, exemplified by ViT-H achieving 80.5%, without any
bells-and-whistles. Curation code and training data distribution on metadata is
made available at https://github.com/facebookresearch/MetaCLIP.
