init commit

whisperx/tokenizer.py

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+import os
+from dataclasses import dataclass
+from functools import lru_cache
+from typing import List, Optional, Tuple, Union
+
+import numpy as np
+import torch
+from transformers import GPT2TokenizerFast
+
+LANGUAGES = {
+    "en": "english",
+    "zh": "chinese",
+    "de": "german",
+    "es": "spanish",
+    "ru": "russian",
+    "ko": "korean",
+    "fr": "french",
+    "ja": "japanese",
+    "pt": "portuguese",
+    "tr": "turkish",
+    "pl": "polish",
+    "ca": "catalan",
+    "nl": "dutch",
+    "ar": "arabic",
+    "sv": "swedish",
+    "it": "italian",
+    "id": "indonesian",
+    "hi": "hindi",
+    "fi": "finnish",
+    "vi": "vietnamese",
+    "he": "hebrew",
+    "uk": "ukrainian",
+    "el": "greek",
+    "ms": "malay",
+    "cs": "czech",
+    "ro": "romanian",
+    "da": "danish",
+    "hu": "hungarian",
+    "ta": "tamil",
+    "no": "norwegian",
+    "th": "thai",
+    "ur": "urdu",
+    "hr": "croatian",
+    "bg": "bulgarian",
+    "lt": "lithuanian",
+    "la": "latin",
+    "mi": "maori",
+    "ml": "malayalam",
+    "cy": "welsh",
+    "sk": "slovak",
+    "te": "telugu",
+    "fa": "persian",
+    "lv": "latvian",
+    "bn": "bengali",
+    "sr": "serbian",
+    "az": "azerbaijani",
+    "sl": "slovenian",
+    "kn": "kannada",
+    "et": "estonian",
+    "mk": "macedonian",
+    "br": "breton",
+    "eu": "basque",
+    "is": "icelandic",
+    "hy": "armenian",
+    "ne": "nepali",
+    "mn": "mongolian",
+    "bs": "bosnian",
+    "kk": "kazakh",
+    "sq": "albanian",
+    "sw": "swahili",
+    "gl": "galician",
+    "mr": "marathi",
+    "pa": "punjabi",
+    "si": "sinhala",
+    "km": "khmer",
+    "sn": "shona",
+    "yo": "yoruba",
+    "so": "somali",
+    "af": "afrikaans",
+    "oc": "occitan",
+    "ka": "georgian",
+    "be": "belarusian",
+    "tg": "tajik",
+    "sd": "sindhi",
+    "gu": "gujarati",
+    "am": "amharic",
+    "yi": "yiddish",
+    "lo": "lao",
+    "uz": "uzbek",
+    "fo": "faroese",
+    "ht": "haitian creole",
+    "ps": "pashto",
+    "tk": "turkmen",
+    "nn": "nynorsk",
+    "mt": "maltese",
+    "sa": "sanskrit",
+    "lb": "luxembourgish",
+    "my": "myanmar",
+    "bo": "tibetan",
+    "tl": "tagalog",
+    "mg": "malagasy",
+    "as": "assamese",
+    "tt": "tatar",
+    "haw": "hawaiian",
+    "ln": "lingala",
+    "ha": "hausa",
+    "ba": "bashkir",
+    "jw": "javanese",
+    "su": "sundanese",
+}
+
+# language code lookup by name, with a few language aliases
+TO_LANGUAGE_CODE = {
+    **{language: code for code, language in LANGUAGES.items()},
+    "burmese": "my",
+    "valencian": "ca",
+    "flemish": "nl",
+    "haitian": "ht",
+    "letzeburgesch": "lb",
+    "pushto": "ps",
+    "panjabi": "pa",
+    "moldavian": "ro",
+    "moldovan": "ro",
+    "sinhalese": "si",
+    "castilian": "es",
+}
+
+
+@dataclass(frozen=True)
+class Tokenizer:
+    """A thin wrapper around `GPT2TokenizerFast` providing quick access to special tokens"""
+
+    tokenizer: "GPT2TokenizerFast"
+    language: Optional[str]
+    sot_sequence: Tuple[int]
+
+    def encode(self, text, **kwargs):
+        return self.tokenizer.encode(text, **kwargs)
+
+    def decode(self, token_ids: Union[int, List[int], np.ndarray, torch.Tensor], **kwargs):
+        return self.tokenizer.decode(token_ids, **kwargs)
+
+    def decode_with_timestamps(self, tokens) -> str:
+        """
+        Timestamp tokens are above the special tokens' id range and are ignored by `decode()`.
+        This method decodes given tokens with timestamps tokens annotated, e.g. "<|1.08|>".
+        """
+        outputs = [[]]
+        for token in tokens:
+            if token >= self.timestamp_begin:
+                timestamp = f"<|{(token - self.timestamp_begin) * 0.02:.2f}|>"
+                outputs.append(timestamp)
+                outputs.append([])
+            else:
+                outputs[-1].append(token)
+        outputs = [s if isinstance(s, str) else self.tokenizer.decode(s) for s in outputs]
+        return "".join(outputs)
+
+    @property
+    @lru_cache()
+    def eot(self) -> int:
+        return self.tokenizer.eos_token_id
+
+    @property
+    @lru_cache()
+    def sot(self) -> int:
+        return self._get_single_token_id("<|startoftranscript|>")
+
+    @property
+    @lru_cache()
+    def sot_lm(self) -> int:
+        return self._get_single_token_id("<|startoflm|>")
+
+    @property
+    @lru_cache()
+    def sot_prev(self) -> int:
+        return self._get_single_token_id("<|startofprev|>")
+
+    @property
+    @lru_cache()
+    def no_speech(self) -> int:
+        return self._get_single_token_id("<|nospeech|>")
+
+    @property
+    @lru_cache()
+    def no_timestamps(self) -> int:
+        return self._get_single_token_id("<|notimestamps|>")
+
+    @property
+    @lru_cache()
+    def timestamp_begin(self) -> int:
+        return self.tokenizer.all_special_ids[-1] + 1
+
+    @property
+    @lru_cache()
+    def language_token(self) -> int:
+        """Returns the token id corresponding to the value of the `language` field"""
+        if self.language is None:
+            raise ValueError(f"This tokenizer does not have language token configured")
+
+        additional_tokens = dict(
+            zip(
+                self.tokenizer.additional_special_tokens,
+                self.tokenizer.additional_special_tokens_ids,
+            )
+        )
+        candidate = f"<|{self.language}|>"
+        if candidate in additional_tokens:
+            return additional_tokens[candidate]
+
+        raise KeyError(f"Language {self.language} not found in tokenizer.")
+
+    @property
+    @lru_cache()
+    def all_language_tokens(self) -> Tuple[int]:
+        result = []
+        for token, token_id in zip(
+            self.tokenizer.additional_special_tokens,
+            self.tokenizer.additional_special_tokens_ids,
+        ):
+            if token.strip("<|>") in LANGUAGES:
+                result.append(token_id)
+        return tuple(result)
+
+    @property
+    @lru_cache()
+    def all_language_codes(self) -> Tuple[str]:
+        return tuple(self.decode([l]).strip("<|>") for l in self.all_language_tokens)
+
+    @property
+    @lru_cache()
+    def sot_sequence_including_notimestamps(self) -> Tuple[int]:
+        return tuple(list(self.sot_sequence) + [self.no_timestamps])
+
+    @property
+    @lru_cache()
+    def non_speech_tokens(self) -> Tuple[int]:
+        """
+        Returns the list of tokens to suppress in order to avoid any speaker tags or non-speech
+        annotations, to prevent sampling texts that are not actually spoken in the audio, e.g.
+
+        - ♪♪♪
+        - ( SPEAKING FOREIGN LANGUAGE )
+        - [DAVID] Hey there,
+
+        keeping basic punctuations like commas, periods, question marks, exclamation points, etc.
+        """
+        symbols = list("\"#()*+/:;<=>@[\\]^_`{|}~「」『』")
+        symbols += "<< >> <<< >>> -- --- -( -[ (' (\" (( )) ((( ))) [[ ]] {{ }} ♪♪ ♪♪♪".split()
+
+        # symbols that may be a single token or multiple tokens depending on the tokenizer.
+        # In case they're multiple tokens, suppress the first token, which is safe because:
+        # These are between U+2640 and U+267F miscellaneous symbols that are okay to suppress
+        # in generations, and in the 3-byte UTF-8 representation they share the first two bytes.
+        miscellaneous = set("♩♪♫♬♭♮♯")
+        assert all(0x2640 <= ord(c) <= 0x267F for c in miscellaneous)
+
+        # allow hyphens "-" and single quotes "'" between words, but not at the beginning of a word
+        result = {self.tokenizer.encode(" -")[0], self.tokenizer.encode(" '")[0]}
+        for symbol in symbols + list(miscellaneous):
+            for tokens in [self.tokenizer.encode(symbol), self.tokenizer.encode(" " + symbol)]:
+                if len(tokens) == 1 or symbol in miscellaneous:
+                    result.add(tokens[0])
+
+        return tuple(sorted(result))
+
+    def _get_single_token_id(self, text) -> int:
+        tokens = self.tokenizer.encode(text)
+        assert len(tokens) == 1, f"{text} is not encoded as a single token"
+        return tokens[0]
+
+
+@lru_cache(maxsize=None)
+def build_tokenizer(name: str = "gpt2"):
+    os.environ["TOKENIZERS_PARALLELISM"] = "false"
+    path = os.path.join(os.path.dirname(__file__), "assets", name)
+    tokenizer = GPT2TokenizerFast.from_pretrained(path)
+
+    specials = [
+        "<|startoftranscript|>",
+        *[f"<|{lang}|>" for lang in LANGUAGES.keys()],
+        "<|translate|>",
+        "<|transcribe|>",
+        "<|startoflm|>",
+        "<|startofprev|>",
+        "<|nospeech|>",
+        "<|notimestamps|>",
+    ]
+
+    tokenizer.add_special_tokens(dict(additional_special_tokens=specials))
+    return tokenizer
+
+
+@lru_cache(maxsize=None)
+def get_tokenizer(
+    multilingual: bool,
+    *,
+    task: Optional[str] = None,  # Literal["transcribe", "translate", None]
+    language: Optional[str] = None,
+) -> Tokenizer:
+    if language is not None:
+        language = language.lower()
+        if language not in LANGUAGES:
+            if language in TO_LANGUAGE_CODE:
+                language = TO_LANGUAGE_CODE[language]
+            else:
+                raise ValueError(f"Unsupported language: {language}")
+
+    if multilingual:
+        tokenizer_name = "multilingual"
+        task = task or "transcribe"
+        language = language or "en"
+    else:
+        tokenizer_name = "gpt2"
+        task = None
+        language = None
+
+    tokenizer = build_tokenizer(name=tokenizer_name)
+    all_special_ids: List[int] = tokenizer.all_special_ids
+    sot: int = all_special_ids[1]
+    translate: int = all_special_ids[-6]
+    transcribe: int = all_special_ids[-5]
+
+    langs = tuple(LANGUAGES.keys())
+    sot_sequence = [sot]
+    if language is not None:
+        sot_sequence.append(sot + 1 + langs.index(language))
+    if task is not None:
+        sot_sequence.append(transcribe if task == "transcribe" else translate)
+
+    return Tokenizer(tokenizer=tokenizer, language=language, sot_sequence=tuple(sot_sequence))