ultralytics 8.0.203 DDP argparse and Tracker fixes (#6007)

ultralytics/trackers/track.py

@@ -1,6 +1,7 @@
 # Ultralytics YOLO 🚀, AGPL-3.0 license
 
 from functools import partial
+from pathlib import Path
 
 import torch
 
@@ -40,8 +41,12 @@ def on_predict_start(predictor, persist=False):
 def on_predict_postprocess_end(predictor):
     """Postprocess detected boxes and update with object tracking."""
     bs = predictor.dataset.bs
-    im0s = predictor.batch[1]
+    path, im0s = predictor.batch[:2]
+
     for i in range(bs):
+        if predictor.vid_path[i] != str(predictor.save_dir / Path(path[i]).name):  # new video
+            predictor.trackers[i].reset()
+
         det = predictor.results[i].boxes.cpu().numpy()
         if len(det) == 0:
             continue