hermes-agent/tools/tts_streaming.py
Brooklyn Nicholson 393c100a92 feat(voice): speech-interrupted latch in the TTS streaming core
mark_speech_interrupted() / take_speech_interrupted(): a one-shot,
TTL'd (120s) latch plus SPEECH_INTERRUPTED_NOTE. Barge-in paths mark
it when they cut live speech; the next turn's submit path pops it and
prepends the note to the model-bound message — API-call local, never
persisted, so history and prompt caching are untouched.
2026-07-22 17:53:06 -05:00

222 lines
8 KiB
Python

"""Provider-agnostic streaming TTS: sentence text → int16 PCM chunk iterator.
The keystone of Hermes' conversational voice UX. `stream_tts_to_speaker`
(``tools.tts_tool``) owns the sentence buffer, sounddevice output, and
stop/queue protocol; this module owns the *provider* half — turning one
sentence into audio the moment it's ready, so playback starts on sentence one
instead of after the whole reply.
Two provider shapes, one contract (int16 mono PCM at ``sample_rate``):
* **True streamers** (`StreamingTTSProvider.stream`) — chunked APIs
(ElevenLabs pcm_24000, OpenAI pcm, …) that yield audio as it synthesizes.
Lowest time-to-first-audio.
* **Everyone else** — providers with no chunked API still get per-*sentence*
playback via the proven sync `text_to_speech_tool` path (handled by the
dispatcher, not here), so edge (the default) is conversational too.
Adding a streamer is `@register("name")` on a `StreamingTTSProvider` subclass;
the dispatcher, config gate (`tts.<name>.streaming`), and resolver come free.
"""
from __future__ import annotations
import logging
import re
import time
from abc import ABC, abstractmethod
from typing import Callable, Dict, Iterator, List, Optional
from tools.tts_tool import _get_provider, get_env_value
logger = logging.getLogger(__name__)
# ---------------------------------------------------------------------------
# Interruption latch — lets the model know it was cut off mid-speech
# ---------------------------------------------------------------------------
# When the user barges in on a spoken reply (talks over it, types, hits the
# record key), the surface marks the latch; the next turn's submit path takes
# it and prepends SPEECH_INTERRUPTED_NOTE to the model-bound message (API-call
# local — never persisted, same as the CLI's model-switch notes). The TTL
# keeps a stale barge from annotating an unrelated message minutes later.
SPEECH_INTERRUPTED_NOTE = (
"[Note: the user interrupted your previous spoken reply before it finished.]"
)
_INTERRUPT_TTL_S = 120.0
_interrupted_at: Optional[float] = None
def mark_speech_interrupted() -> None:
global _interrupted_at
_interrupted_at = time.monotonic()
def take_speech_interrupted() -> bool:
"""Pop the latch; True when a barge happened within the TTL."""
global _interrupted_at
at, _interrupted_at = _interrupted_at, None
return at is not None and time.monotonic() - at < _INTERRUPT_TTL_S
# Sentence boundary: after .!? followed by whitespace, or a blank line.
SENTENCE_BOUNDARY_RE = re.compile(r"(?<=[.!?])(?:\s|\n)|(?:\n\n)")
_THINK_BLOCK_RE = re.compile(r"<think[\s>].*?</think>", flags=re.DOTALL)
class SentenceChunker:
"""Incremental sentence cutter for LLM token deltas.
Shared by the speaker pipeline (`stream_tts_to_speaker`) and the
speak-stream WebSocket so every surface cuts speech identically. Strips
``<think>`` blocks (even split across deltas) and merges fragments shorter
than *min_len* into the following sentence, so "Ha!" rides along with the
sentence after it instead of stalling as a tiny clip.
"""
def __init__(self, min_len: int = 20):
self.min_len = min_len
self.buf = ""
def feed(self, delta: str) -> List[str]:
"""Absorb *delta*; return every complete sentence now ready to speak."""
self.buf = _THINK_BLOCK_RE.sub("", self.buf + delta)
if "<think" in self.buf and "</think>" not in self.buf:
return [] # open think tag — the closing tag may arrive next delta
out: List[str] = []
start = 0 # skip boundaries that would leave the head too short
while m := SENTENCE_BOUNDARY_RE.search(self.buf, start):
head = self.buf[: m.end()]
if len(head.strip()) < self.min_len:
start = m.end()
continue
out.append(head)
self.buf = self.buf[m.end():]
start = 0
return out
def flush(self) -> List[str]:
"""Drain the tail (end-of-text or long-idle flush)."""
tail = _THINK_BLOCK_RE.sub("", self.buf).strip()
self.buf = ""
return [tail] if tail else []
# ---------------------------------------------------------------------------
# ABC + registry
# ---------------------------------------------------------------------------
class StreamingTTSProvider(ABC):
"""Yields raw int16, little-endian, mono PCM chunks at ``sample_rate``."""
sample_rate: int = 24000
channels: int = 1
sample_width: int = 2 # bytes/sample (int16)
def __init__(self, tts_config: Dict, section: Dict):
self.tts_config = tts_config
self.section = section
@staticmethod
@abstractmethod
def available() -> bool:
"""True when this provider's credentials/SDK are usable right now."""
@abstractmethod
def stream(self, text: str) -> Iterator[bytes]:
"""Yield PCM chunks for ``text``. Raise on failure (caller logs)."""
_REGISTRY: Dict[str, type[StreamingTTSProvider]] = {}
def register(name: str) -> Callable[[type[StreamingTTSProvider]], type[StreamingTTSProvider]]:
def _wrap(cls: type[StreamingTTSProvider]) -> type[StreamingTTSProvider]:
_REGISTRY[name] = cls
return cls
return _wrap
def resolve_streaming_provider(
tts_config: Dict,
preferred: Optional[str] = None,
) -> Optional[StreamingTTSProvider]:
"""Return a ready streamer for the *configured* provider, else ``None``.
``None`` means "no chunked API for this provider" — the dispatcher then
speaks per-sentence via the sync path, preserving the user's chosen voice.
We never silently swap to a different provider just to get streaming.
"""
name = (preferred or _get_provider(tts_config)).lower().strip()
cls = _REGISTRY.get(name)
if cls is None or not cls.available():
return None
try:
return cls(tts_config, tts_config.get(name) or {})
except Exception as exc: # pragma: no cover - defensive
logger.debug("streaming provider %s init failed: %s", name, exc)
return None
# ---------------------------------------------------------------------------
# Providers
# ---------------------------------------------------------------------------
@register("elevenlabs")
class ElevenLabsStreamer(StreamingTTSProvider):
"""ElevenLabs chunked HTTP → pcm_24000 (the original reference path)."""
sample_rate = 24000
@staticmethod
def available() -> bool:
return bool(get_env_value("ELEVENLABS_API_KEY"))
def stream(self, text: str) -> Iterator[bytes]:
from tools.tts_tool import (
DEFAULT_ELEVENLABS_STREAMING_MODEL_ID,
DEFAULT_ELEVENLABS_VOICE_ID,
_import_elevenlabs,
)
client = _import_elevenlabs()(api_key=get_env_value("ELEVENLABS_API_KEY"))
voice_id = self.section.get("voice_id", DEFAULT_ELEVENLABS_VOICE_ID)
model_id = self.section.get(
"streaming_model_id",
self.section.get("model_id", DEFAULT_ELEVENLABS_STREAMING_MODEL_ID),
)
yield from client.text_to_speech.convert(
text=text,
voice_id=voice_id,
model_id=model_id,
output_format="pcm_24000",
)
@register("openai")
class OpenAIStreamer(StreamingTTSProvider):
"""OpenAI speech with ``response_format=pcm`` (24 kHz mono int16)."""
sample_rate = 24000
@staticmethod
def available() -> bool:
return bool(get_env_value("OPENAI_API_KEY"))
def stream(self, text: str) -> Iterator[bytes]:
from openai import OpenAI
client = OpenAI(
api_key=get_env_value("OPENAI_API_KEY"),
base_url=get_env_value("OPENAI_BASE_URL") or None,
)
model = self.section.get("model", "gpt-4o-mini-tts")
voice = self.section.get("voice", "alloy")
with client.audio.speech.with_streaming_response.create(
model=model,
voice=voice,
input=text,
response_format="pcm",
) as response:
yield from response.iter_bytes()