added decoder for keypad mapping

README.md

@@ -19,7 +19,7 @@ $ sudo cp dtmf.py /usr/local/bin/dtmf
 You have to give a wav file (you can try to convert it with `ffmpeg -i audio.mp3 audio.wav` for example).
 
 ```
-Usage: dtmf [-h] [-v] [-l] [-r] [-d] [-t F] [-i T] file.wav
+Usage: dtmf [-h] [-v] [-l] [-r] [-d] [-t F] [-i T] [-p] file.wav
 
 optional arguments:
   -h, --help     show this help message and exit
@@ -29,6 +29,7 @@ optional arguments:
   -d, --debug    show graphs to debug
   -t F           acceptable frequency error (in hertz, 20 by default)
   -i T           process by T seconds intervals (0.05 by default)
+  -p, --processletters process keypad mapping (contigent on having a proper decode using the basic feature without --verbose mode)
 ```
 
 ## Examples
@@ -45,6 +46,13 @@ $ dtmf perfect-example.wav
 ```
 As you can see it works perfectly, we have a classical French phone number.
 
+```
+$ dtmf -p perfect-example2.wav
+62#74#23#43#81#93
+Result:  62#74#23#43#81#93
+Decoded result based on Keypad:  NSCITY
+```
+
 #### The non-perfect case
 ```
 $ dtmf not-perfect-example.wav

dtmf.py

@@ -5,6 +5,32 @@
 from scipy.io import wavfile
 import argparse
 
+keypad = {
+    "2": "ABC",
+    "3": "DEF",
+    "4": "GHI",
+    "5": "JKL",
+    "6": "MNO",
+    "7": "PQRS",
+    "8": "TUV",
+    "9": "WXYZ"
+}
+
+def decode_sequence(sequence: str) -> str:
+    parts = sequence.split("#")
+    decoded = []
+
+    for part in parts:
+        if len(part) != 2:  # must be 2 digits
+            continue
+        digit, index = part[0], int(part[1])
+
+        if digit in keypad and 1 <= index <= len(keypad[digit]):
+            decoded.append(keypad[digit][index - 1])
+        else:
+            decoded.append("?")
+    return "".join(decoded)
+
 dtmf = {(697, 1209): "1", (697, 1336): "2", (697, 1477): "3", (770, 1209): "4", (770, 1336): "5", (770, 1477): "6", (852, 1209): "7", (852, 1336): "8", (852, 1477): "9", (941, 1209): "*", (941, 1336): "0", (941, 1477): "#", (697, 1633): "A", (770, 1633): "B", (852, 1633): "C", (941, 1633): "D"}
 
 
@@ -15,6 +41,7 @@
 parser.add_argument("-d", "--debug", help="show graphs to debug", action="store_true")
 parser.add_argument("-t", type=int, metavar="F", help="acceptable frequency error (in hertz, 20 by default)", default=20)
 parser.add_argument("-i", type=float, metavar='T', help="process by T seconds intervals (0.04 by default)", default=0.04)
+parser.add_argument("-p", "--processletters", help="process keypad mapping", action="store_true")
 
 parser.add_argument('file', type=argparse.FileType('r'))
 
@@ -63,6 +90,7 @@
 debug = args.debug
 verbose = args.verbose
 c = ""
+final_result = ""
 
 if debug:
     print("Warning:\nThe debug mode is very uncomfortable: you need to close each window to continue.\nFeel free to kill the process doing CTRL+C and then close the window.\n")
@@ -164,12 +192,18 @@
             c = ""
         elif dtmf[(lf,hf)] != c or verbose:
             c = dtmf[(lf,hf)]
+            final_result = final_result + c
             print(c, end='', flush=True)
 
         if debug:
             plt.show()
 
     print()
 
+    print("Result: ", final_result)
+
+    if args.processletters:
+        print("Decoded result based on Keypad: ", decode_sequence(final_result))
+
 except KeyboardInterrupt:
     print("\nCTRL+C detected: exiting...")