We expect most users will only require this functionality. Follow these steps to download the official RedCaps annotations and images and arrange all the data in recommended directory structure:

/path/to/redcaps/
├── annotations/
│   ├── abandoned_2017.json
│   ├── abandoned_2017.json
│   ├── ...
│   ├── itookapicture_2019.json
│   ├── itookapicture_2020.json
│   ├── <subreddit>_<year>.json
│   └── ...
│
└── images/
    ├── abandoned/
    │   ├── guli1.jpg
    |   └── ...
    │
    ├── itookapicture/
    │   ├── 1bd79.jpg
    |   └── ...
    │
    ├── <subreddit>/
    │   ├── <image_id>.jpg
    │   ├── ...
    └── ...

1. Create an empty directory and symlink it relative to this code directory:

   cd redcaps-downloader
   
   # Edit path here:
   mkdir -p /path/to/redcaps
   ln -s /path/to/redcaps ./datasets/redcaps

2. Download official RedCaps annotations from Dropbox and unzip them.

   cd datasets/redcaps
   wget https://www.dropbox.com/s/cqtdpsl4hewlli1/redcaps_v1.0_annotations.zip?dl=1
   unzip redcaps_v1.0_annotations.zip

3. Download images by using redcaps download-imgs command (for a single annotation file).

   for ann_file in ./datasets/redcaps/annotations/*.json; do
       redcaps download-imgs -a $ann_file --save-to path/to/images --resize 512 -j 4
       # Set --resize -1 to turn off resizing shorter edge (saves disk space).
   done

   Parallelize download by changing -j. RedCaps images are sourced from Reddit, Imgur and Flickr, each have their own request limits. This code contains approximate sleep intervals to manage them. Use multiple machines (= different IP addresses) or a cluster to massively parallelize downloading.

That's it, you are all set to use RedCaps!

If you wish to use this dataset to train large vision-language models like CLIP, we recommend arranging the dataset as TAR files of images and JSON annotations (subreddit name and caption), in a format compatible with PyTorch Webdataset.

This command converts all downloaded annotations and images to TAR files containing 1000 image-text pairs, skipping instances whose images were missing:

for ann in datasets/redcaps/annotations/*.json; do
  python scripts/make_tarfiles.py --input $ann \
    --image-dir datasets/redcaps/images --output-dir datasets/redcaps/tarfiles
done

Apart from downloading the officially released dataset, this tool supports downloading image-text data from any subreddit – you can reproduce the entire collection pipeline as well as create your own variant of RedCaps! Here, we show how to collect annotations from r/roses (2020) as an example. Follow these steps for any subreddit and years.

RedCaps annotations are extracted from image post metadata, which are served by the Pushshift API and official Reddit API. These APIs are authentication-based, and one must sign up for developer access to obtain API keys (one-time setup):

1. Copy ./credentials.template.json to ./credentials.json. Its contents are as follows:

   {
       "reddit": {
           "client_id": "Your client ID here",
           "client_secret": "Your client secret here",
           "username": "Your Reddit username here",
           "password": "Your Reddit password here",
           "user_agent": "<username>: <device name>"
       },
       "imgur": {
           "client_id": "Your client ID here",
           "client_secret": "Your client secret here"
       }
   }

2. Register a new Reddit app here. Reddit will provide a Client ID and Client Secret tokens - fill them in ./credentials.json. For more details, refer to the Reddit OAuth2 wiki. Enter your Reddit account name and password in ./credentials.json. Set User Agent to anything and keep it unchanged (e.g. your name).

3. Register a new Imgur App by following instructions here. Fill the provided Client ID and Client Secret in ./credentials.json.

4. Download pre-trained weights of an NSFW detection model.

   wget https://s3.amazonaws.com/nsfwdetector/nsfw.299x299.h5 -P ./datasets/redcaps/models

1. download-anns: Dowload annotations of image posts made in a single month (e.g. January).

   redcaps download-anns --subreddit roses --month 2020-01 -o ./datasets/redcaps/annotations
   
   # Similarly, download annotations for all months of 2020:
   for ((month = 1; month <= 12; month += 1)); do
       redcaps download-anns --subreddit roses --month 2020-$month -o ./datasets/redcaps/annotations
   done

   • NOTE: You may not get all the annotations present in official release as some of them may have disappeared (deleted) over time. After this step, the dataset directory would contain 12 annotation files:

       ./datasets/redcaps/
       └── annotations/
           ├── roses_2020-01.json
           ├── roses_2020-02.json
           ├── ...
           └── roses_2020-12.json
   

2. merge: Merge all the monthly annotation files into a single file.

   redcaps merge ./datasets/redcaps/annotations/roses_2020-* \
       -o ./datasets/redcaps/annotations/roses_2020.json --delete-old

   • --delete-old will remove individual files after merging. After this step, the merged file will replace individual monthly files:

       ./datasets/redcaps/
       └── annotations/
           └── roses_2020.json
   

3. download-imgs: Download all images for this annotation file. This step is same as (3) in basic usage.

   redcaps download-imgs --annotations ./datasets/redcaps/annotations/roses_2020.json \
       --resize 512 -j 4 -o ./datasets/redcaps/images --update-annotations

   • --update-annotations removes annotations whose images were not downloaded.

4. filter-words: Filter all instances whose captions contain potentially harmful language. Any caption containing one of the 400 blocklisted words will be removed. This command modifies the annotation file in-place and deletes the corresponding images from disk.

   redcaps filter-words --annotations ./datasets/redcaps/annotations/roses_2020.json \
       --images ./datasets/redcaps/images

5. filter-nsfw: Remove all instances having images that are flagged by an off-the-shelf NSFW detector. This command also modifies the annotation file in-place and deletes the corresponding images from disk.

   redcaps filter-nsfw --annotations ./datasets/redcaps/annotations/roses_2020.json \
       --images ./datasets/redcaps/images \
       --model ./datasets/redcaps/models/nsfw.299x299.h5

6. filter-faces: Remove all instances having images with faces detected by an off-the-shelf face detector. This command also modifies the annotation file in-place and deletes the corresponding images from disk.

   redcaps filter-faces --annotations ./datasets/redcaps/annotations/roses_2020.json \
       --images ./datasets/redcaps/images  # Model weights auto-downloaded

7. validate: All the above steps create a single annotation file (and downloads images) similar to official RedCaps annotations. To double-check this, run the following command and expect no errors to be printed.

   redcaps validate --annotations ./datasets/redcaps/annotations/roses_2020.json