need blockage on train end

callbacks.py

@@ -1,4 +1,5 @@
-import subprocess
+# import subprocess
+import os
 from pathlib import Path
 
 from lightning import Callback
@@ -69,4 +70,5 @@ class SaveImageCallback(Callback):
                 # w, h = self.figsize[0] * self.dpi, self.figsize[1] * self.dpi
                 w, h = 7680, 4320
                 _cmd = f'ffmpeg -r {fps} -f image2 -i {log_dir}/e%04d.png -vcodec libx264 -crf 25 -pix_fmt yuv420p -vf "scale={w}:{h}:force_original_aspect_ratio=decrease,pad={w}:{h}:(ow-iw)/2:(oh-ih)/2:color=white" {log_dir}/a{version}.mp4'
-                _ = subprocess.Popen(_cmd, shell=True)
+                # _ = subprocess.Popen(_cmd, shell=True)
+                os.system(_cmd)