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a9a9005f31
Auto-TTS previously fed raw chat Markdown and compact symbols straight to the speech provider, so units were read as stray letters and headings or bullets ran together. This routes spoken text through a new normalizer, tools/tts_text_normalize.prepare_spoken_text, that expands units (for example a temperature written with the degree symbol becomes "degrees Celsius") and flattens Markdown into a transcript-like script with sentence pauses. The normalizer is best-effort: if it ever fails the code falls back to the previous markdown-strip behavior, so auto-TTS keeps working. The Telegram voice caption uses the same normalized text. Includes a unit test.
224 lines
9.5 KiB
Python
224 lines
9.5 KiB
Python
"""Utilities for preparing assistant text for speech synthesis.
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The TTS provider should receive a spoken script, not raw chat Markdown. This
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module centralises the lightweight, deterministic cleanup used by explicit TTS
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calls and gateway auto-TTS replies.
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Non-ASCII characters are written as escapes on purpose so the file stays free of
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invisible/look-alike glyphs.
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"""
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from __future__ import annotations
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import html
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import re
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# Sentinel appended to former heading lines so smooth_whitespace_for_tts can
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# fold a heading into the sentence that follows it ("Weather, it will be sunny")
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# rather than leaving a bare "Weather." label that reads abruptly aloud.
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_HEAD = "\x00"
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_MD_CODE_BLOCK_RE = re.compile(r"```[\s\S]*?```")
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_MD_LINK_RE = re.compile(r"\[([^\]]+)\]\((?:[^()]|\([^)]*\))*\)")
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_MD_IMAGE_RE = re.compile(r"!\[([^\]]*)\]\((?:[^()]|\([^)]*\))*\)")
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_MD_INLINE_CODE_RE = re.compile(r"`([^`]+)`")
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_MD_BOLD_RE = re.compile(r"\*\*(.+?)\*\*", flags=re.DOTALL)
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_MD_UNDERSCORE_BOLD_RE = re.compile(r"__(.+?)__", flags=re.DOTALL)
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_MD_ITALIC_RE = re.compile(r"(?<!\*)\*(?!\*)(.+?)(?<!\*)\*(?!\*)", flags=re.DOTALL)
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_MD_UNDERSCORE_ITALIC_RE = re.compile(r"(?<!_)_(?!_)(.+?)(?<!_)_(?!_)", flags=re.DOTALL)
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_MD_STRIKE_RE = re.compile(r"~~(.+?)~~", flags=re.DOTALL)
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_MD_HEADING_LINE_RE = re.compile(r"^[ \t]{0,3}#{1,6}[ \t]+(.+?)[ \t]*#*[ \t]*$", flags=re.MULTILINE)
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_MD_BLOCKQUOTE_RE = re.compile(r"^\s*>\s?", flags=re.MULTILINE)
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_MD_LIST_ITEM_RE = re.compile(r"^\s*(?:[-*+]|\d+[.)])\s+", flags=re.MULTILINE)
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_MD_HR_RE = re.compile(r"^\s*[-*_]{3,}\s*$", flags=re.MULTILINE)
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_MD_TABLE_PIPE_RE = re.compile(r"\s*\|\s*")
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_URL_RE = re.compile(r"https?://\S+")
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# Broad emoji / pictograph cleanup. Voice providers vary a lot here; most read
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# emojis as awkward labels, so keep the speech script calm and literal.
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_EMOJI_RE = re.compile(
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"["
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"\U0001F1E6-\U0001F1FF"
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"\U0001F300-\U0001F5FF"
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"\U0001F600-\U0001F64F"
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"\U0001F680-\U0001F6FF"
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"\U0001F700-\U0001F77F"
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"\U0001F780-\U0001F7FF"
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"\U0001F800-\U0001F8FF"
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"\U0001F900-\U0001F9FF"
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"\U0001FA00-\U0001FAFF"
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"☀-➿"
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"]+",
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flags=re.UNICODE,
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)
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_VARIATION_SELECTOR_RE = re.compile("[︎️]")
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def strip_markdown_for_tts(text: str) -> str:
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"""Strip Markdown/Telegram formatting while preserving readable words."""
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if not text:
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return ""
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text = html.unescape(str(text))
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text = _MD_CODE_BLOCK_RE.sub(" ", text)
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text = _MD_IMAGE_RE.sub(lambda m: f" {m.group(1)} " if m.group(1) else " ", text)
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text = _MD_LINK_RE.sub(r"\1", text)
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text = _URL_RE.sub("", text)
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text = _MD_INLINE_CODE_RE.sub(r"\1", text)
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text = _MD_BOLD_RE.sub(r"\1", text)
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text = _MD_UNDERSCORE_BOLD_RE.sub(r"\1", text)
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text = _MD_ITALIC_RE.sub(r"\1", text)
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text = _MD_UNDERSCORE_ITALIC_RE.sub(r"\1", text)
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text = _MD_STRIKE_RE.sub(r"\1", text)
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# Mark headings (do not just delete the marker): the whitespace pass folds a
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# heading into the sentence after it so speech says "Weather, it will be
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# sunny" instead of a clipped "Weather." then a separate sentence.
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text = _MD_HEADING_LINE_RE.sub(lambda m: m.group(1).rstrip() + _HEAD, text)
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text = _MD_BLOCKQUOTE_RE.sub("", text)
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text = _MD_LIST_ITEM_RE.sub("", text)
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text = _MD_HR_RE.sub("", text)
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# Pipe tables are terrible read aloud. Turn any leftover pipes into pauses
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# instead of letting a provider speak "vertical bar".
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text = _MD_TABLE_PIPE_RE.sub("; ", text)
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return text
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def _normalize_temperature_ranges(text: str) -> str:
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# 11-17 degrees C -> "11 to 17 degrees Celsius" (en/em dash or hyphen).
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text = re.sub(
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r"(?<!\w)([-+\u2212]?\d+(?:\.\d+)?)\s*[\u2013\u2014-]\s*([-+\u2212]?\d+(?:\.\d+)?)\s*°\s*C\b",
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lambda m: f"{m.group(1).replace(chr(0x2212), '-')} to {m.group(2).replace(chr(0x2212), '-')} degrees Celsius",
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text,
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flags=re.IGNORECASE,
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)
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text = re.sub(
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r"(?<!\w)([-+\u2212]?\d+(?:\.\d+)?)\s*[\u2013\u2014-]\s*([-+\u2212]?\d+(?:\.\d+)?)\s*°\s*F\b",
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lambda m: f"{m.group(1).replace(chr(0x2212), '-')} to {m.group(2).replace(chr(0x2212), '-')} degrees Fahrenheit",
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text,
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flags=re.IGNORECASE,
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)
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return text
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def normalize_symbols_for_tts(text: str) -> str:
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"""Expand common symbols/shorthand into words a TTS engine reads well."""
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if not text:
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return ""
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text = str(text)
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text = re.sub("[ ]", " ", text) # non-breaking / thin spaces
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text = text.replace("\u2212", "-") # minus sign
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text = text.replace("…", "...") # ellipsis
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text = _normalize_temperature_ranges(text)
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# Temperatures with a number. Do this before generic degree handling.
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text = re.sub(r"(?<!\w)([-+]?\d+(?:\.\d+)?)\s*°\s*C\b", r"\1 degrees Celsius", text, flags=re.IGNORECASE)
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text = re.sub(r"(?<!\w)([-+]?\d+(?:\.\d+)?)\s*°\s*F\b", r"\1 degrees Fahrenheit", text, flags=re.IGNORECASE)
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# Bare units with no leading number ("measured in degrees C").
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text = re.sub(r"°\s*C\b", "degrees Celsius", text, flags=re.IGNORECASE)
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text = re.sub(r"°\s*F\b", "degrees Fahrenheit", text, flags=re.IGNORECASE)
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# Any remaining degree symbol (angles, stray cases).
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text = re.sub(r"(?<!\w)([-+]?\d+(?:\.\d+)?)\s*°", r"\1 degrees", text)
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text = text.replace("°", " degrees")
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# Common weather/travel units.
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text = re.sub(r"(?<=\d)\s*km\s*/\s*h\b", " kilometres per hour", text, flags=re.IGNORECASE)
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text = re.sub(r"(?<=\d)\s*km/h\b", " kilometres per hour", text, flags=re.IGNORECASE)
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text = re.sub(r"(?<=\d)\s*mm\b", " millimetres", text, flags=re.IGNORECASE)
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text = re.sub(r"(?<=\d)\s*cm\b", " centimetres", text, flags=re.IGNORECASE)
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text = re.sub(r"(?<=\d)\s*m\b", " metres", text, flags=re.IGNORECASE)
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# Numeric rates only ("5/month" -> "5 per month"). Requiring digit-then-letter
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# keeps "and/or", "N/A", "TCP/IP" and dates like "2026/06" intact.
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text = re.sub(r"(?<=\d)\s*/\s*(?=[A-Za-z])", " per ", text)
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# Money and percentages. The integer part must END in a digit so a trailing
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# comma ("A$50, ...") is not swallowed into the spoken amount.
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text = re.sub(r"NZ\$\s*([\d,]*\d(?:\.\d+)?)", r"\1 New Zealand dollars", text, flags=re.IGNORECASE)
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text = re.sub(r"A\$\s*([\d,]*\d(?:\.\d+)?)", r"\1 Australian dollars", text, flags=re.IGNORECASE)
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text = re.sub(r"US\$\s*([\d,]*\d(?:\.\d+)?)", r"\1 US dollars", text, flags=re.IGNORECASE)
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text = re.sub(r"€\s*([\d,]*\d(?:\.\d+)?)", r"\1 euros", text)
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text = re.sub(r"£\s*([\d,]*\d(?:\.\d+)?)", r"\1 pounds", text)
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text = re.sub(r"\$\s*([\d,]*\d(?:\.\d+)?)", r"\1 dollars", text)
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text = re.sub(r"(?<=\d)\s*%", " percent", text)
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# Operators and separators that commonly leak from formatted answers.
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text = text.replace("&", " and ")
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text = re.sub("[•◦▪▫]", " ", text) # bullet glyphs
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text = text.replace("→", " to ") # ->
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text = text.replace("⇒", " to ") # =>
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text = text.replace("≈", " about ") # almost equal
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text = text.replace("~", " about ")
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text = _VARIATION_SELECTOR_RE.sub("", text)
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text = _EMOJI_RE.sub("", text)
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return text
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def smooth_whitespace_for_tts(text: str) -> str:
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"""Collapse visual formatting into calm spoken paragraphs.
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A former heading line (marked with the _HEAD sentinel) folds into the next
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content line as a spoken lead-in: "Weather" + "It will be sunny" becomes
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"Weather, It will be sunny." A heading with no content after it becomes its
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own short sentence.
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"""
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if not text:
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return ""
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raw_lines = text.splitlines()
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add_sentence_pauses = sum(1 for raw_line in raw_lines if raw_line.replace(_HEAD, "").strip()) > 1
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lines: list[str] = []
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pending_heading: str | None = None
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def flush_pending() -> None:
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nonlocal pending_heading
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if pending_heading is not None:
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lines.append(pending_heading.rstrip(".:;,") + ".")
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pending_heading = None
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for raw_line in raw_lines:
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is_heading = raw_line.rstrip().endswith(_HEAD)
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line = raw_line.replace(_HEAD, "").strip()
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if not line:
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# Hold a pending heading across blank lines so it still folds into
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# the next real content line; otherwise just collapse the blank.
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if pending_heading is None and lines and lines[-1] != "":
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lines.append("")
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continue
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if is_heading:
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flush_pending()
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pending_heading = line.rstrip(".:;,")
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continue
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if pending_heading is not None:
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line = f"{pending_heading.rstrip('.:;,')}, {line}"
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pending_heading = None
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if add_sentence_pauses and line[-1] not in ".!?;:":
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line += "."
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lines.append(line)
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flush_pending()
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text = "\n".join(lines)
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text = re.sub(r"\n{3,}", "\n\n", text)
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text = re.sub(r"[ \t]{2,}", " ", text)
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text = re.sub(r"\s+([,.;:!?])", r"\1", text)
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text = re.sub(r"([,.;:!?])([A-Za-z])", r"\1 \2", text)
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text = re.sub(r"\.{4,}", "...", text)
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return text.strip()
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def prepare_spoken_text(text: str, max_chars: int | None = 4000) -> str:
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"""Return a TTS-friendly script from assistant text.
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Deterministic cleanup, not a semantic rewrite: it removes Markdown, expands
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common symbols such as a degree-Celsius sign to "degrees Celsius", and turns
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visual line formatting into speakable sentence pauses.
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"""
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spoken = strip_markdown_for_tts(text)
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spoken = normalize_symbols_for_tts(spoken)
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spoken = smooth_whitespace_for_tts(spoken)
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if max_chars is not None and max_chars > 0 and len(spoken) > max_chars:
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spoken = spoken[:max_chars].rstrip()
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return spoken
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