--- a
+++ b/tools/data/gym/trim_subaction.py
@@ -0,0 +1,52 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import os
+import os.path as osp
+import subprocess
+
+import mmcv
+
+data_root = '../../../data/gym'
+anno_root = f'{data_root}/annotations'
+
+event_anno_file = f'{anno_root}/event_annotation.json'
+event_root = f'{data_root}/events'
+subaction_root = f'{data_root}/subactions'
+
+events = os.listdir(event_root)
+events = set(events)
+annotation = mmcv.load(event_anno_file)
+
+mmcv.mkdir_or_exist(subaction_root)
+
+for k, v in annotation.items():
+    if k + '.mp4' not in events:
+        print(f'video {k[:11]} has not been downloaded '
+              f'or the event clip {k} not generated')
+        continue
+
+    video_path = osp.join(event_root, k + '.mp4')
+
+    for subaction_id, subaction_anno in v.items():
+        timestamps = subaction_anno['timestamps']
+        start_time, end_time = timestamps[0][0], timestamps[-1][1]
+        subaction_name = k + '_' + subaction_id
+
+        output_filename = subaction_name + '.mp4'
+
+        command = [
+            'ffmpeg', '-i',
+            '"%s"' % video_path, '-ss',
+            str(start_time), '-t',
+            str(end_time - start_time), '-c:v', 'libx264', '-c:a', 'copy',
+            '-threads', '8', '-loglevel', 'panic',
+            '"%s"' % osp.join(subaction_root, output_filename)
+        ]
+        command = ' '.join(command)
+        try:
+            subprocess.check_output(
+                command, shell=True, stderr=subprocess.STDOUT)
+        except subprocess.CalledProcessError:
+            print(
+                f'Trimming of the Subaction {subaction_name} of Event '
+                f'{k} Failed',
+                flush=True)