The prototxt files are the Caffe-based CNN model definition and training parameters used in the following paper: 

CNN in MRF: Video Object Segmentation via Inference in A CNN-Based Higher-Order Spatio-Temporal MRF, 
Linchao Bao, Baoyuan Wu, and Wei Liu,
CVPR 2018.

Note that the Caffe version for the prototxt is forked from [https://bitbucket.org/aquariusjay/deeplab-public-ver2].

