diff --git a/README.md b/README.md
index 5adecf427a36b3e423589c27fe1fe8035f6502ca..9471adb6123f84bf8394abba7e9a7863bd1268dd 100644
--- a/README.md
+++ b/README.md
@@ -73,17 +73,21 @@ Having a CUDA-capable GPU is optional, but can greatly reduce processing time in
 
 ## Autokara
 
-To execute AutoKara from scratch on a MKV video file :
+To use Autokara, you need :
+ - A media file of the song (video, or pre-extracted vocals)
+ - An ASS file with the lyrics, split by syllable
+
+To execute AutoKara on a MKV video file and an ASS file containing the lyrics (ASS will be overwritten):
 ```bash
-$ python autokara.py video.mkv output.ass
+$ python autokara.py video.mkv lyrics.ass
 ```
 
-To execute AutoKara with existing syl splits and line timings :
+To output to a different file (and keep the original) :
 ```bash
-$ python autokara.py video.mkv output.ass --ref reference.ass
+$ python autokara.py video.mkv lyrics.ass -o output.ass
 ```
 
-To execute AutoKara on a (pre-extracted) WAV vocals file :
+To execute AutoKara on a (pre-extracted) WAV (or OGG, MP3, ...) vocals file, pass the `--vocals` flag :
 ```bash
 $ python autokara.py vocals.wav output.ass --vocals
 ```
@@ -110,6 +114,12 @@ Batch preprocessing (vocals + ASS extraction) of all videos in a directory :
 $ ./preprocess_media.sh video_folder output_folder
 ```
 
+A visualization tool, mainly intended for debug.
+Does the same as autokara.py, but instead of writing to a file, plots a graphic with onset times, spectrogram, probability curves,... 
+Does not work on video files, only separated vocals audio files
+```bash
+$ python plot_syls.py vocals.wav lyrics.ass
+```
 
 
 
diff --git a/plot_syls.py b/plot_syls.py
index 527c1e473522ad78fd8904e4baf0e8b7a41e96e4..e86960430761fc37dcc54ebfc60dbcc1a1361da1 100644
--- a/plot_syls.py
+++ b/plot_syls.py
@@ -5,6 +5,7 @@ import re
 import matplotlib.pyplot as plt
 import scipy.signal as sg
 import parselmouth
+import argparse
 
 from autosyl.assUtils import getSyls, timeToDate, dateToTime 
 from autosyl.LyricsAlignment.wrapper import align, preprocess_from_file
@@ -19,11 +20,17 @@ from autosyl.LyricsAlignment.wrapper import align, preprocess_from_file
 #
 ##############################################################################
 
-songfile = sys.argv[1]
-if(len(sys.argv) >= 3):
-    reference_syls = getSyls(sys.argv[2])
-else:
-    reference_syls = None
+
+parser = argparse.ArgumentParser(description='AutoKara - Automatic karaoke timing tool')
+parser.add_argument("vocals_file", type=str, help="The audio file to time")
+parser.add_argument("ass_file", type=str, help="The ASS file with lyrics to time")
+
+args = parser.parse_args()
+
+
+songfile = args.vocals_file
+reference_syls, line_meta = getSyls(sys.argv[2])
+
 
 print(reference_syls)