Minor changes to roidb generation

* Remove video number from video path. New video path format is frame_root/video_name

* check chunk id before loading chunk.json

preprocess/virat/roidb_generation.py

@@ -18,10 +18,11 @@ def generate_testing_video_db(json_index_path, chunk_file, chunk_id):
   use_chunks = False
   with open(json_index_path, 'r') as f:
     all_annotations = json.load(f)
-  with open(chunk_file, 'r') as f:
-    all_chunks = json.load(f)
-    if chunk_id > 0:
-      use_chunks = True
+
+  if chunk_id > 0:
+    use_chunks = True
+    with open(chunk_file, 'r') as f:
+      all_chunks = json.load(f)
       chunk_key = "Chunk" + str(chunk_id)
       if chunk_key in all_chunks.keys():
         chunk_videos = all_chunks[chunk_key]["files"]
@@ -47,7 +48,7 @@ def generate_testing_video_db(json_index_path, chunk_file, chunk_id):
     for index  in range(len(start_indices)):
         start_index = start_indices[index]
         end_index = end_indices[index]
-        video_prefix = video_name.split(".")[0]
+        video_prefix = os.path.splitext(video_name)[0]
         if video_prefix not in video_db.keys():
             video_db[video_prefix] = [[start_index, end_index, -1]]
         else:
@@ -198,7 +199,7 @@ def generate_roidb_pkl(test_mode, kpf_mode,
         video_db = generate_density_training_video_db(annotation_dirs, classes)
     
     for video in video_db:
-      video_folder = os.path.join(frames_root, get_relative_path(video))
+      video_folder = os.path.join(frames_root, video)
       if not os.path.exists(video_folder):
         print ("Skipping video, could not find its folder : " + video_folder)
         sys.exit()