Update README.md

README.md

@@ -54,7 +54,7 @@ https://github.com/donghao51/MultiOOD
 MultiOOD is based on five public action recognition datasets (HMDB51, UCF101, EPIC-Kitchens, HAC, and Kinetics-600). 
 
 ### Prepare Datasets
-1. Download HMDB51 video data from [link](http://serre-lab.clps.brown.edu/wp-content/uploads/2013/10/hmdb51_org.rar) and extract. Download HMDB51 optical flow data from [link](https://huggingface.co/datasets/hdong51/MultiOOD/blob/main/hmdb51_flow_mp4.tar.gz) and extract. The directory structure should be modified to match:
+1. Download HMDB51 video data from [link](https://serre-lab.clps.brown.edu/resource/hmdb-a-large-human-motion-database/#Downloads) and extract. Download HMDB51 optical flow data from [link](https://huggingface.co/datasets/hdong51/MultiOOD/blob/main/hmdb51_flow_mp4.tar.gz) and extract. The directory structure should be modified to match:
 
 ```
 HMDB51