Fixed video labelling after `subset` call for HMDB51 dataset (hmdb51.py)...

Fixed video labelling after `subset` call for HMDB51 dataset (hmdb51.py) (EDIT: UCF101 as well) (#1240)

* Fixed video labelling after subset for HMDB51 dataset

* Fixed video labelling after subset for HMDB51 dataset
Co-authored-by: Eric Tang <etang21@stanford.edu>
Co-authored-by: Ryan Cao <ryancao@stanford.edu>

* UCF 101 Labeling fixes

- Analogous fix to HMDB51 to maintain correct labels after the train-test split
- Additional change to the `select_fold` method in `ucf101.py` to correctly reflect the annotation format
Co-authored-by: Ryan Cao <ryancao@stanford.edu>
Co-authored-by: Eric Tang <etang21@stanford.edu>

torchvision/datasets/hmdb51.py

@@ -65,8 +65,8 @@ class HMDB51(VisionDataset):
         self.classes = classes
         video_list = [x[0] for x in self.samples]
         video_clips = VideoClips(video_list, frames_per_clip, step_between_clips)
-        indices = self._select_fold(video_list, annotation_path, fold, train)
-        self.video_clips = video_clips.subset(indices)
+        self.indices = self._select_fold(video_list, annotation_path, fold, train)
+        self.video_clips = video_clips.subset(self.indices)
         self.transform = transform
 
     def _select_fold(self, video_list, annotation_path, fold, train):
@@ -89,7 +89,7 @@ class HMDB51(VisionDataset):
 
     def __getitem__(self, idx):
         video, audio, info, video_idx = self.video_clips.get_clip(idx)
-        label = self.samples[video_idx][1]
+        label = self.samples[self.indices[video_idx]][1]
 
         if self.transform is not None:
             video = self.transform(video)

torchvision/datasets/ucf101.py

@@ -58,8 +58,8 @@ class UCF101(VisionDataset):
         self.classes = classes
         video_list = [x[0] for x in self.samples]
         video_clips = VideoClips(video_list, frames_per_clip, step_between_clips)
-        indices = self._select_fold(video_list, annotation_path, fold, train)
-        self.video_clips = video_clips.subset(indices)
+        self.indices = self._select_fold(video_list, annotation_path, fold, train)
+        self.video_clips = video_clips.subset(self.indices)
         self.transform = transform
 
     def _select_fold(self, video_list, annotation_path, fold, train):
@@ -81,7 +81,7 @@ class UCF101(VisionDataset):
 
     def __getitem__(self, idx):
         video, audio, info, video_idx = self.video_clips.get_clip(idx)
-        label = self.samples[video_idx][1]
+        label = self.samples[self.indices[video_idx]][1]
 
         if self.transform is not None:
             video = self.transform(video)