vidi-player.py: move the actual processing after the arguments validation

diff --git a/vidi-player.py b/vidi-player.py
index 303d55d..491a3f3 100755 (executable)
--- a/vidi-player.py
+++ b/vidi-player.py
@@ -86,13 +86,6 @@ def main():
         usage()
         return 1
 
-    midi_file = mido.MidiFile(sys.argv[1])
-
-    overlapping_notes = check_overlapping_notes(midi_file)
-    if overlapping_notes:
-        sys.stderr.write("Sorry, supporting only midi file with no overlapping notes on channel 0\n")
-        return 1
-
     if not os.path.isdir(sys.argv[2]):
         sys.stderr.write("The second argument must be the path of the videofont directory\n")
         usage()
@@ -102,6 +95,13 @@ def main():
         sys.stderr.write("File '%s' exists, exiting!\n" % sys.argv[3])
         return 1
 
+    midi_file = mido.MidiFile(sys.argv[1])
+
+    overlapping_notes = check_overlapping_notes(midi_file, 0)
+    if overlapping_notes:
+        sys.stderr.write("Sorry, supporting only midi file with no overlapping notes on channel 0\n")
+        return 1
+
     video_font_path = os.path.realpath(sys.argv[2])
 
     timeline = timeline_from_midi(midi_file, video_font_path)