Extract the Preprocessing for Silero into a file and Improve it (#757)

extensions/silero_tts/tts_preprocessor.py

@@ -0,0 +1,195 @@
+import re
+
+from num2words import num2words
+
+
+punctuation = r'[\s,.?!/)\'\]>]'
+alphabet_map = {
+    "A": " Ei ",
+    "B": " Bee ",
+    "C": " See ",
+    "D": " Dee ",
+    "E": " Eee ",
+    "F": " Eff ",
+    "G": " Jee ",
+    "H": " Eich ",
+    "I": " Eye ",
+    "J": " Jay ",
+    "K": " Kay ",
+    "L": " El ",
+    "M": " Emm ",
+    "N": " Enn ",
+    "O": " Ohh ",
+    "P": " Pee ",
+    "Q": " Queue ",
+    "R": " Are ",
+    "S": " Ess ",
+    "T": " Tee ",
+    "U": " You ",
+    "V": " Vee ",
+    "W": " Double You ",
+    "X": " Ex ",
+    "Y": " Why ",
+    "Z": " Zed "  # Zed is weird, as I (da3dsoul) am American, but most of the voice models sound British, so it matches
+}
+
+
+def preprocess(string):
+    # the order for some of these matter
+    # For example, you need to remove the commas in numbers before expanding them
+    string = remove_surrounded_chars(string)
+    string = string.replace('"', '')
+    string = string.replace('\u201D', '').replace('\u201C', '')  # right and left quote
+    string = string.replace('\u201F', '')  # italic looking quote
+    string = string.replace('\n', ' ')
+    string = convert_num_locale(string)
+    string = replace_negative(string)
+    string = replace_roman(string)
+    string = hyphen_range_to(string)
+    string = num_to_words(string)
+
+    # TODO Try to use a ML predictor to expand abbreviations. It's hard, dependent on context, and whether to actually
+    # try to say the abbreviation or spell it out as I've done below is not agreed upon
+
+    # For now, expand abbreviations to pronunciations
+    # replace_abbreviations adds a lot of unnecessary whitespace to ensure separation
+    string = replace_abbreviations(string)
+    string = replace_lowercase_abbreviations(string)
+
+    # cleanup whitespaces
+    # remove whitespace before punctuation
+    string = re.sub(rf'\s+({punctuation})', r'\1', string)
+    string = string.strip()
+    # compact whitespace
+    string = ' '.join(string.split())
+
+    return string
+
+
+def remove_surrounded_chars(string):
+    # this expression matches to 'as few symbols as possible (0 upwards) between any asterisks' OR
+    # 'as few symbols as possible (0 upwards) between an asterisk and the end of the string'
+    return re.sub(r'\*[^*]*?(\*|$)', '', string)
+
+
+def convert_num_locale(text):
+    # This detects locale and converts it to American without comma separators
+    pattern = re.compile(r'(?:\s|^)\d{1,3}(?:\.\d{3})+(,\d+)(?:\s|$)')
+    result = text
+    while True:
+        match = pattern.search(result)
+        if match is None:
+            break
+
+        start = match.start()
+        end = match.end()
+        result = result[0:start] + result[start:end].replace('.', '').replace(',', '.') + result[end:len(result)]
+
+    # removes comma separators from existing American numbers
+    pattern = re.compile(r'(\d),(\d)')
+    result = pattern.sub(r'\1\2', result)
+
+    return result
+
+
+def replace_negative(string):
+    # handles situations like -5. -5 would become negative 5, which would then be expanded to negative five
+    return re.sub(rf'(\s)(-)(\d+)({punctuation})', r'\1negative \3\4', string)
+
+
+def replace_roman(string):
+    # find a string of roman numerals.
+    # Only 2 or more, to avoid capturing I and single character abbreviations, like names
+    pattern = re.compile(rf'\s[IVXLCDM]{{2,}}{punctuation}')
+    result = string
+    while True:
+        match = pattern.search(result)
+        if match is None:
+            break
+
+        start = match.start()
+        end = match.end()
+        result = result[0:start + 1] + str(roman_to_int(result[start + 1:end - 1])) + result[end - 1:len(result)]
+
+    return result
+
+
+def roman_to_int(s):
+    rom_val = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
+    int_val = 0
+    for i in range(len(s)):
+        if i > 0 and rom_val[s[i]] > rom_val[s[i - 1]]:
+            int_val += rom_val[s[i]] - 2 * rom_val[s[i - 1]]
+        else:
+            int_val += rom_val[s[i]]
+    return int_val
+
+
+def hyphen_range_to(text):
+    pattern = re.compile(r'(\d+)[-–](\d+)')
+    result = pattern.sub(lambda x: x.group(1) + ' to ' + x.group(2), text)
+    return result
+
+
+def num_to_words(text):
+    # 1000 or 10.23
+    pattern = re.compile(r'\d+\.\d+|\d+')
+    result = pattern.sub(lambda x: num2words(float(x.group())), text)
+    return result
+
+
+def replace_abbreviations(string):
+    # abbreviations 1 to 4 characters long. It will get things like A and I, but those are pronounced with their letter
+    pattern = re.compile(rf'(^|[\s(.\'\[<])([A-Z]{{1,4}})({punctuation}|$)')
+    result = string
+    while True:
+        match = pattern.search(result)
+        if match is None:
+            break
+
+        start = match.start()
+        end = match.end()
+        result = result[0:start] + replace_abbreviation(result[start:end]) + result[end:len(result)]
+
+    return result
+
+
+def replace_lowercase_abbreviations(string):
+    # abbreviations 1 to 4 characters long, separated by dots i.e. e.g.
+    pattern = re.compile(rf'(^|[\s(.\'\[<])(([a-z]\.){{1,4}})({punctuation}|$)')
+    result = string
+    while True:
+        match = pattern.search(result)
+        if match is None:
+            break
+
+        start = match.start()
+        end = match.end()
+        result = result[0:start] + replace_abbreviation(result[start:end].upper()) + result[end:len(result)]
+
+    return result
+
+
+def replace_abbreviation(string):
+    result = ""
+    for char in string:
+        result += match_mapping(char)
+
+    return result
+
+
+def match_mapping(char):
+    for mapping in alphabet_map.keys():
+        if char == mapping:
+            return alphabet_map[char]
+
+    return char
+
+
+def __main__(args):
+    print(preprocess(args[1]))
+
+
+if __name__ == "__main__":
+    import sys
+    __main__(sys.argv)