fixed framerate issue

tools/video/mp4-recorder.py

@@ -39,7 +39,6 @@ def record_zed_to_mp4(output_file="output.mp4", fps=30, duration=10):
 
     # Main loop
     frame_count = int(duration * fps)
-    start_time = time.time()
     for i in range(frame_count):
         # Grab the current image
         if zed.grab(runtime_parameters) == sl.ERROR_CODE.SUCCESS:
@@ -55,15 +54,14 @@ def record_zed_to_mp4(output_file="output.mp4", fps=30, duration=10):
             video_writer.write(frame)
 
             # Print status update
-            elapsed_time = time.time() - start_time
+            elapsed_time = i / fps
             print(f"\rRecording... {elapsed_time:.2f}/{duration} seconds", end='')
 
             # # Optional: Display the frame (press 'q' to exit early)
             # cv2.imshow("ZED Video", frame)
             # if cv2.waitKey(1) & 0xFF == ord('q'):
             #     break
 
-
         else:
             print("Frame grab failed")
             break