Discard OOV chars in tokenizer

Discard but store OOV chars with a warninig message
when the OOV char first recognized

TTS/tts/utils/text/tokenizer.py

@@ -8,6 +8,8 @@ from TTS.tts.utils.text.phonemizers import DEF_LANG_TO_PHONEMIZER, get_phonemize
 class TTSTokenizer:
     """🐸TTS tokenizer to convert input characters to token IDs and back.
 
+    Token IDs for OOV chars are discarded but those are stored in `self.not_found_characters` for later.
+
     Args:
         use_phonemes (bool):
             Whether to use phonemes instead of characters. Defaults to False.
@@ -45,14 +47,21 @@ class TTSTokenizer:
         self.add_blank = add_blank
         self.use_eos_bos = use_eos_bos
         self.characters = characters
+        self.not_found_characters = []
         self.phonemizer = phonemizer
 
     def encode(self, text: str) -> List[int]:
         """Encodes a string of text as a sequence of IDs."""
         token_ids = []
         for char in text:
-            idx = self.characters.char_to_id(char)
-            token_ids.append(idx)
+            try:
+                idx = self.characters.char_to_id(char)
+                token_ids.append(idx)
+            except KeyError:
+                # discard but store not found characters
+                if char not in self.not_found_characters:
+                    self.not_found_characters.append(char)
+                    print(f" [!] Character {repr(char)} not found in the vocabulary. Discarding it.")
         return token_ids
 
     def decode(self, token_ids: List[int]) -> str:
@@ -109,6 +118,10 @@ class TTSTokenizer:
         print(f"{indent}| > use_phonemes: {self.use_phonemes}")
         if self.use_phonemes:
             print(f"{indent}| > phonemizer: {self.phonemizer.print_logs(level + 1)}")
+        if len(self.not_found_characters) > 0:
+            print(f"{indent}| > {len(self.not_found_characters)} not found characters:")
+            for char in self.not_found_characters:
+                print(f"{indent}| > {char}")
 
     @staticmethod
     def init_from_config(config: "Coqpit"):