add information for feature mode

README.md

@@ -1,7 +1,8 @@
 # Video Classification Using 3D ResNet
 This is a pytorch code for video (action) classification using 3D ResNet trained by [this code](https://github.com/kenshohara/3D-ResNets-PyTorch).  
 The 3D ResNet is trained on the Kinetics dataset, which includes 400 action classes.  
-This code uses videos as inputs and outputs class names and predicted class scores for each 16 frames.  
+This code uses videos as inputs and outputs class names and predicted class scores for each 16 frames in the score mode.  
+In the feature mode, this code outputs features of 512 dims (after global average pooling) for each 16 frames.  
 
 **Torch (Lua) version of this code is available [here](https://github.com/kenshohara/video-classification-3d-cnn).**