Merge pull request #2937 from aaronng91/speechmatics-tts

Add Speechmatics TTS

src/pipecat/services/speechmatics/tts.py

@@ -0,0 +1,189 @@
+#
+# Copyright (c) 2024–2025, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+"""Speechmatics TTS service integration."""
+
+from typing import AsyncGenerator, Optional
+from urllib.parse import urlencode
+
+import aiohttp
+from loguru import logger
+from pydantic import BaseModel
+
+from pipecat.frames.frames import (
+    ErrorFrame,
+    Frame,
+    TTSAudioRawFrame,
+    TTSStartedFrame,
+    TTSStoppedFrame,
+)
+from pipecat.services.tts_service import TTSService
+from pipecat.utils.tracing.service_decorators import traced_tts
+
+try:
+    from speechmatics.rt import __version__
+except ModuleNotFoundError as e:
+    logger.error(f"Exception: {e}")
+    logger.error(
+        "In order to use Speechmatics, you need to `pip install pipecat-ai[speechmatics]`."
+    )
+    raise Exception(f"Missing module: {e}")
+
+
+class SpeechmaticsTTSService(TTSService):
+    """Speechmatics TTS service implementation.
+
+    This service provides text-to-speech synthesis using the Speechmatics HTTP API.
+    It converts text to speech and returns raw PCM audio data for real-time playback.
+    """
+
+    SPEECHMATICS_SAMPLE_RATE = 16000
+
+    class InputParams(BaseModel):
+        """Optional input parameters for Speechmatics TTS configuration."""
+
+        pass
+
+    def __init__(
+        self,
+        *,
+        api_key: str,
+        base_url: str = "https://preview.tts.speechmatics.com",
+        voice_id: str = "sarah",
+        aiohttp_session: aiohttp.ClientSession,
+        sample_rate: Optional[int] = SPEECHMATICS_SAMPLE_RATE,
+        params: Optional[InputParams] = None,
+        **kwargs,
+    ):
+        """Initialize the Speechmatics TTS service.
+
+        Args:
+            api_key: Speechmatics API key for authentication.
+            base_url: Base URL for Speechmatics TTS API.
+            voice_id: Voice model to use for synthesis.
+            aiohttp_session: Shared aiohttp session for HTTP requests.
+            sample_rate: Audio sample rate in Hz.
+            params: Optional[InputParams]: Input parameters for the service.
+            **kwargs: Additional arguments passed to TTSService.
+        """
+        if sample_rate and sample_rate != self.SPEECHMATICS_SAMPLE_RATE:
+            logger.warning(
+                f"Speechmatics TTS only supports {self.SPEECHMATICS_SAMPLE_RATE}Hz sample rate. "
+                f"Current rate of {sample_rate}Hz may cause issues."
+            )
+        super().__init__(sample_rate=sample_rate, **kwargs)
+
+        # Service parameters
+        self._api_key: str = api_key
+        self._base_url: str = base_url
+        self._session = aiohttp_session
+
+        # Check we have required attributes
+        if not self._api_key:
+            raise ValueError("Missing Speechmatics API key")
+
+        # Default parameters
+        self._params = params or SpeechmaticsTTSService.InputParams()
+
+        # Set voice from constructor parameter
+        self.set_voice(voice_id)
+
+    def can_generate_metrics(self) -> bool:
+        """Check if this service can generate processing metrics.
+
+        Returns:
+            True, as Speechmatics service supports metrics generation.
+        """
+        return True
+
+    @traced_tts
+    async def run_tts(self, text: str) -> AsyncGenerator[Frame, None]:
+        """Generate speech from text using Speechmatics' HTTP API.
+
+        Args:
+            text: The text to synthesize into speech.
+
+        Yields:
+            Frame: Audio frames containing the synthesized speech.
+        """
+        logger.debug(f"{self}: Generating TTS [{text}]")
+
+        headers = {
+            "Authorization": f"Bearer {self._api_key}",
+            "Content-Type": "application/json",
+        }
+
+        payload = {
+            "text": text,
+        }
+
+        url = _get_endpoint_url(self._base_url, self._voice_id, self.sample_rate)
+
+        try:
+            await self.start_ttfb_metrics()
+
+            async with self._session.post(url, json=payload, headers=headers) as response:
+                if response.status != 200:
+                    error_message = f"Speechmatics TTS error: HTTP {response.status}"
+                    logger.error(error_message)
+                    yield ErrorFrame(error=error_message)
+                    return
+
+                await self.start_tts_usage_metrics(text)
+
+                yield TTSStartedFrame()
+
+                # Process the response in streaming chunks
+                first_chunk = True
+                buffer = b""
+
+                async for chunk in response.content.iter_any():
+                    if not chunk:
+                        continue
+                    if first_chunk:
+                        await self.stop_ttfb_metrics()
+                        first_chunk = False
+
+                    buffer += chunk
+
+                    # Emit all complete 2-byte int16 samples from buffer
+                    if len(buffer) >= 2:
+                        complete_samples = len(buffer) // 2
+                        complete_bytes = complete_samples * 2
+
+                        audio_data = buffer[:complete_bytes]
+                        buffer = buffer[complete_bytes:]  # Keep remaining bytes for next iteration
+
+                        yield TTSAudioRawFrame(
+                            audio=audio_data,
+                            sample_rate=self.sample_rate,
+                            num_channels=1,
+                        )
+
+        except Exception as e:
+            logger.exception(f"Error generating TTS: {e}")
+            yield ErrorFrame(error=f"Speechmatics TTS error: {str(e)}")
+        finally:
+            yield TTSStoppedFrame()
+
+
+def _get_endpoint_url(base_url: str, voice: str, sample_rate: int) -> str:
+    """Format the TTS endpoint URL with voice, output format, and version params.
+
+    Args:
+        base_url: The base URL for the TTS endpoint.
+        voice: The voice model to use.
+        sample_rate: The audio sample rate.
+
+    Returns:
+        str: The formatted TTS endpoint URL.
+    """
+    query_params = {}
+    query_params["output_format"] = f"pcm_{sample_rate}"
+    query_params["sm-app"] = f"pipecat/{__version__}"
+    query = urlencode(query_params)
+
+    return f"{base_url}/generate/{voice}?{query}"