diff --git a/README.md b/README.md
index d43a0bbadfc647f9c3eba7d8be9218fccd0b9b63..7b27cb455b816dfc4fe6a8e690a34e53c6019d80 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,8 @@ This code requires you have Keras 2 and TensorFlow 1 or greater installed. Pleas
 
 `pip install -r requirements.txt`
 
+You must also have `ffmpeg` installed in order to extract the video files. If `ffmpeg` isn't in your system path (ie. `which ffmpeg` doesn't return its path, or you're on an OS other than *nix), you'll need to update the path to `ffmpeg` in `data/2_extract_files.py`.
+
 ## Getting the data
 
 First, download the dataset from UCF into the `data` folder:
diff --git a/requirements.txt b/requirements.txt
index 791d4c26a12256dcd607cfb4e2f47df3b2bd9eb9..245bb4cbf65ac8b279d726ad5b4642843b9bcb97 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,3 +3,5 @@ numpy>=1.12.1
 pandas>=0.19.2
 tqdm>=4.11.2
 matplotlib>=2.0.0
+Pillow>=2.1.0
+h5py>=2.7.0