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This repo contains code for our ECCV 2020 paper.

LEMMA: A Multi-view Dataset for LEarning Multi-agent Multi-task Activities

Baoxiong Jia, Yixin Chen, Siyuan Huang, Yixin Zhu, Song-Chun Zhu

Proceedings of the European Conference on Computer Vision (ECCV), 2020


For the dataset, please check out our website for details.



Our code is adapted from the SlowFast network repo, please check that the basic requirements from this repo are satisfied.

Additional dependencies include:

  • numpy
  • torch
  • pathlib
  • Pillow
  • ffmpeg-python
  • opencv-python


This repo contains code for the baseline experiments conducted for compositional action recognition and action/task anticipation.

We provide basic configuration files for different architectures and views. Default configurations can be found in config/ . On top of it, we provide sample configurations customized for differnt view and model in settings/{model_type}_{view_type}_plain_hoi.yaml. Other parameters can be found in the two main entrance, and respectively for recognition and anticipation task.

For the recognition task, we used word embeddings from GloVe. The extracted embeddings for verbs/nouns used in this project are provided in embedding.p. Please set the cfg.EMBED_PATH correctly to use the embeddings.

A sample command for running the experiments would be

python --cfg settings/slowfast_tpv_plain_hoi.yaml EXP.MODEL_TYPE branch EXP.VIEW_TYPE tpv

This is running the Slowfast-branching model on third-person-view recordings reported in the paper. You might as well change the running settings according to your environment, such arguments in include NUM_GPUS, TRAIN.BATCH_SIZE, TEST.BATCH_SIZE, etc.. Paths for the dataset should be adjusted according to your local arrangement, this include data path, annotations and intermediate paths. You can search for /home/baoxiong/... for all the paths we used and switch them to the corresponding ones on your local machines.

For the anticipation task, we use extracted features from plain slowfast model.

A smple command for running the anticipation would be

python --model featurebank --use_extra True --extra tpv --task False 

This is running the LFB model with extra tpv features provided for the action anticipation task. Similarly, paths should be correctly set to run this experiment.

Path Setting

To run the experiments correctly, you need to change file path in yaml file as well as config/ You can find the meaning of each path corresponding to their variable name as well as the sample path listed in codes. To correctly run for action/task anticipation, we provided an feature extraction file in utils/exp_utils/ You will need to change the sys.path.append() (for running this file directly as script), model_cfg (for selecting model setting), cfg.OUTPUT_DIR (for output directory of features), cfg.TRAIN.CHECKPOINT_FILE_PATH (model checkpoint to use), for running this script directly. For these paths, you can change them directly in the file, or the first two in the file or arguments and change cfg.{} in the yaml file.


If you find the paper and/or the code helpful, please cite

    author={Jia, Baoxiong and Chen, Yixin and Huang, Siyuan and Zhu, Yixin and Zhu, Song-Chun}, 
    title={LEMMA: A Multiview Dataset for Learning Multi-agent Multi-view Activities}, 
    booktitle={Proceedings of the European Conference on Computer Vision (ECCV)}, 


We thank (i) Tao Yuan at UCLA for designing the an-notation tool, (ii) Lifeng Fan, Qing Li, Tengyu Liu at UCLA and ZhouqianJiang for helpful discussions, and (iii) colleagues from UCLA VCLA for assistingthe endeavor of post-processing this massive dataset.

We also gratefully thank the authors from SlowFast network for open-sourcing their code.


Code for ECCV 2020 paper "LEMMA: A Multi-view Dataset for LEarning Multi-agent Multi-task Activities"






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