General ultralytics==8.0.6 updates (#351)

Co-authored-by: Dzmitry Plashchynski <plashchynski@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/yolo/engine/predictor.py

@@ -240,7 +240,7 @@ class BasePredictor:
                 if isinstance(self.vid_writer[idx], cv2.VideoWriter):
                     self.vid_writer[idx].release()  # release previous video writer
                 if vid_cap:  # video
-                    fps = vid_cap.get(cv2.CAP_PROP_FPS)
+                    fps = int(vid_cap.get(cv2.CAP_PROP_FPS))  # integer required, floats produce error in MP4 codec
                     w = int(vid_cap.get(cv2.CAP_PROP_FRAME_WIDTH))
                     h = int(vid_cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
                 else:  # stream

ultralytics/yolo/engine/trainer.py

@@ -506,10 +506,12 @@ class BaseTrainer:
     def check_resume(self):
         resume = self.args.resume
         if resume:
-            last = Path(check_file(resume) if isinstance(resume, str) else get_latest_run())
+            last = Path(check_file(resume) if isinstance(resume, (str, Path)) else get_latest_run())
             args_yaml = last.parent.parent / 'args.yaml'  # train options yaml
-            if args_yaml.is_file():
-                args = get_config(args_yaml)  # replace
+            assert args_yaml.is_file(), \
+                FileNotFoundError('Resume checkpoint f{last} not found. '
+                                  'Please pass a valid checkpoint to resume from, i.e. yolo resume=path/to/last.pt')
+            args = get_config(args_yaml)  # replace
             args.model, resume = str(last), True  # reinstate
             self.args = args
         self.resume = resume