#!/usr/bin/env python3 # Copyright 2026 Xiaomi Corp. (authors: Han Zhu) # # See ../../LICENSE for clarification regarding multiple authors # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Text duration estimation for TTS generation. Provides ``RuleDurationEstimator``, which estimates audio duration from text using character phonetic weights across 600+ languages. Used by ``OmniVoice.generate()`` to determine output length when no duration is specified. """ import bisect import unicodedata from functools import lru_cache from typing import Optional class RuleDurationEstimator: def __init__(self): # ========================================== # 1. Phonetic Weights Table # ========================================== # The weight represents the relative speaking time compared to # a standard Latin letter. # Benchmark: 1.0 = One Latin Character (~40-50ms) self.weights = { # --- Logographic (1 char = full syllable/word) --- "cjk": 3.0, # Chinese, Japanese Kanji, etc. # --- Syllabic / Blocks "hangul": 2.5, # Korean Hangul "kana": 2.2, # Japanese Hiragana/Katakana "ethiopic": 3.0, # Amharic/Ge'ez "yi": 3.0, # Yi script # --- Abugida (Consonant-Vowel complexes) --- "indic": 1.8, # Hindi, Bengali, Tamil, etc. "thai_lao": 1.5, # Thai, Lao "khmer_myanmar": 1.8, # Khmer, Myanmar # --- Abjad (Consonant-heavy) --- "arabic": 1.5, # Arabic, Persian, Urdu "hebrew": 1.5, # Hebrew # --- Alphabet (Segmental) --- "latin": 1.0, # English, Spanish, French, Vietnamese, etc. (Baseline) "cyrillic": 1.0, # Russian, Ukrainian "greek": 1.0, # Greek "armenian": 1.0, # Armenian "georgian": 1.0, # Georgian # --- Symbols & Misc --- "punctuation": 0.5, # Pause capability "space": 0.2, # Word boundary/Breath (0.05 / 0.22) "digit": 3.5, # Numbers "mark": 0.0, # Diacritics/Accents (Silent modifiers) "default": 1.0, # Fallback for unknown scripts } # ========================================== # 2. Unicode Range Mapping # ========================================== # Format: (End_Codepoint, Type_Key) # Used for fast binary search (bisect). self.ranges = [ (0x02AF, "latin"), # Latin (Basic, Supplement, Ext, IPA) (0x03FF, "greek"), # Greek & Coptic (0x052F, "cyrillic"), # Cyrillic (0x058F, "armenian"), # Armenian (0x05FF, "hebrew"), # Hebrew (0x077F, "arabic"), # Arabic, Syriac, Arabic Supplement (0x089F, "arabic"), # Arabic Extended-B (+ Syriac Supp) (0x08FF, "arabic"), # Arabic Extended-A (0x097F, "indic"), # Devanagari (0x09FF, "indic"), # Bengali (0x0A7F, "indic"), # Gurmukhi (0x0AFF, "indic"), # Gujarati (0x0B7F, "indic"), # Oriya (0x0BFF, "indic"), # Tamil (0x0C7F, "indic"), # Telugu (0x0CFF, "indic"), # Kannada (0x0D7F, "indic"), # Malayalam (0x0DFF, "indic"), # Sinhala (0x0EFF, "thai_lao"), # Thai & Lao (0x0FFF, "indic"), # Tibetan (Abugida) (0x109F, "khmer_myanmar"), # Myanmar (0x10FF, "georgian"), # Georgian (0x11FF, "hangul"), # Hangul Jamo (0x137F, "ethiopic"), # Ethiopic (0x139F, "ethiopic"), # Ethiopic Supplement (0x13FF, "default"), # Cherokee (0x167F, "default"), # Canadian Aboriginal Syllabics (0x169F, "default"), # Ogham (0x16FF, "default"), # Runic (0x171F, "default"), # Tagalog (Baybayin) (0x173F, "default"), # Hanunoo (0x175F, "default"), # Buhid (0x177F, "default"), # Tagbanwa (0x17FF, "khmer_myanmar"), # Khmer (0x18AF, "default"), # Mongolian (0x18FF, "default"), # Canadian Aboriginal Syllabics Ext (0x194F, "indic"), # Limbu (0x19DF, "indic"), # Tai Le & New Tai Lue (0x19FF, "khmer_myanmar"), # Khmer Symbols (0x1A1F, "indic"), # Buginese (0x1AAF, "indic"), # Tai Tham (0x1B7F, "indic"), # Balinese (0x1BBF, "indic"), # Sundanese (0x1BFF, "indic"), # Batak (0x1C4F, "indic"), # Lepcha (0x1C7F, "indic"), # Ol Chiki (Santali) (0x1C8F, "cyrillic"), # Cyrillic Extended-C (0x1CBF, "georgian"), # Georgian Extended (0x1CCF, "indic"), # Sundanese Supplement (0x1CFF, "indic"), # Vedic Extensions (0x1D7F, "latin"), # Phonetic Extensions (0x1DBF, "latin"), # Phonetic Extensions Supplement (0x1DFF, "default"), # Combining Diacritical Marks Supplement (0x1EFF, "latin"), # Latin Extended Additional (Vietnamese) (0x309F, "kana"), # Hiragana (0x30FF, "kana"), # Katakana (0x312F, "cjk"), # Bopomofo (Pinyin) (0x318F, "hangul"), # Hangul Compatibility Jamo (0x9FFF, "cjk"), # CJK Unified Ideographs (Main) (0xA4CF, "yi"), # Yi Syllables (0xA4FF, "default"), # Lisu (0xA63F, "default"), # Vai (0xA69F, "cyrillic"), # Cyrillic Extended-B (0xA6FF, "default"), # Bamum (0xA7FF, "latin"), # Latin Extended-D (0xA82F, "indic"), # Syloti Nagri (0xA87F, "default"), # Phags-pa (0xA8DF, "indic"), # Saurashtra (0xA8FF, "indic"), # Devanagari Extended (0xA92F, "indic"), # Kayah Li (0xA95F, "indic"), # Rejang (0xA97F, "hangul"), # Hangul Jamo Extended-A (0xA9DF, "indic"), # Javanese (0xA9FF, "khmer_myanmar"), # Myanmar Extended-B (0xAA5F, "indic"), # Cham (0xAA7F, "khmer_myanmar"), # Myanmar Extended-A (0xAADF, "indic"), # Tai Viet (0xAAFF, "indic"), # Meetei Mayek Extensions (0xAB2F, "ethiopic"), # Ethiopic Extended-A (0xAB6F, "latin"), # Latin Extended-E (0xABBF, "default"), # Cherokee Supplement (0xABFF, "indic"), # Meetei Mayek (0xD7AF, "hangul"), # Hangul Syllables (0xFAFF, "cjk"), # CJK Compatibility (0xFDFF, "arabic"), # Arabic Presentation Forms-A (0xFE6F, "default"), # Variation Selectors (0xFEFF, "arabic"), # Arabic Presentation Forms-B (0xFFEF, "latin"), # Fullwidth Latin ] self.breakpoints = [r[0] for r in self.ranges] @lru_cache(maxsize=4096) def _get_char_weight(self, char): """Determines the weight of a single character.""" code = ord(char) if (65 <= code <= 90) or (97 <= code <= 122): return self.weights["latin"] if code == 32: return self.weights["space"] # Ignore arabic Tatweel if code == 0x0640: return self.weights["mark"] category = unicodedata.category(char) if category.startswith("M"): return self.weights["mark"] if category.startswith("P") or category.startswith("S"): return self.weights["punctuation"] if category.startswith("Z"): return self.weights["space"] if category.startswith("N"): return self.weights["digit"] # 3. Binary search for Unicode Block (此时区间里绝不会再混进标点符号) idx = bisect.bisect_left(self.breakpoints, code) if idx < len(self.ranges): script_type = self.ranges[idx][1] return self.weights.get(script_type, self.weights["default"]) # 4. Handle upper planes (CJK Ext B/C/D, Historic scripts) if code > 0x20000: return self.weights["cjk"] return self.weights["default"] def calculate_total_weight(self, text): """Sums up the normalized weights for a string.""" return sum(self._get_char_weight(c) for c in text) def estimate_duration( self, target_text: str, ref_text: str, ref_duration: float, low_threshold: Optional[float] = 50, boost_strength: float = 3, ) -> float: """ Args: target_text (str): The text for which we want to estimate the duration. ref_text (str): The reference text that was used to measure the ref_duration. ref_duration (float): The actual duration it took to speak the ref_text. low_threshold (float): The minimum duration threshold below which the estimation will be considered unreliable. boost_strength (float): Controls the power-curve boost for short durations. Higher values boost small durations more aggressively. 1 = no boost (linear), 2 = sqrt-like Returns: float: The estimated duration for the target_text based on the ref_text and ref_duration. """ if ref_duration <= 0 or not ref_text: return 0.0 ref_weight = self.calculate_total_weight(ref_text) if ref_weight == 0: return 0.0 speed_factor = ref_weight / ref_duration target_weight = self.calculate_total_weight(target_text) estimated_duration = target_weight / speed_factor if low_threshold is not None and estimated_duration < low_threshold: alpha = 1.0 / boost_strength return low_threshold * (estimated_duration / low_threshold) ** alpha else: return estimated_duration # ========================================== # Example Usage # ========================================== if __name__ == "__main__": estimator = RuleDurationEstimator() ref_txt = "Hello, world." ref_dur = 1.5 test_cases = [ ("Hindi (With complex marks)", "नमस्ते दुनिया"), ("Arabic (With vowels)", "مَرْحَبًا بِالْعَالَم"), ("Vietnamese (Lots of diacritics)", "Chào thế giới"), ("Chinese", "你好，世界！"), ("Mixed Emoji", "Hello 🌍! This is fun 🎉"), ] print("--- Reference ---") print(f"Reference Text: '{ref_txt}'") print(f"Reference Duration: {ref_dur}s") print("-" * 30) for lang, txt in test_cases: est_time = estimator.estimate_duration(txt, ref_txt, ref_dur) weight = estimator.calculate_total_weight(txt) print(f"[{lang}]") print(f"Text: {txt}") print(f"Total Weight: {weight:.2f}") print(f"Estimated Duration: {est_time:.2f} s") print("-" * 30)