minor fixes

video_tool.py

@@ -2,10 +2,19 @@ import ffmpeg
 
 
 def convert_video_to_audio(input_file, output_file, start_time, end_time):
-    ffmpeg.input(input_file, ss=start_time, to=end_time).audio.output(
-        output_file, format="wav").run(overwrite_output=True)
+    (
+        ffmpeg
+        .input(input_file, ss=start_time, to=end_time)
+        .audio
+        .output(output_file, format="wav")
+        .run(overwrite_output=True)
+    )
 
 
 def add_subtitle_to_video(input_file, subtitle_file, output_file, start_time, end_time):
-    ffmpeg.input(input_file, ss=start_time, to=end_time).output(
-        output_file, vf='subtitles=' + subtitle_file, preset='ultrafast', acodec='copy').run(overwrite_output=True)
+    (
+        ffmpeg
+        .input(input_file, ss=start_time, to=end_time)
+        .output(output_file, vf='subtitles=' + subtitle_file, preset='ultrafast', acodec='copy')
+        .run(overwrite_output=True)
+    )