app.py

from fastapi import FastAPI, Request, WebSocket, WebSocketDisconnect
from fastapi.responses import StreamingResponse, JSONResponse
import outetts
import io
import json
import base64
import struct
import os 
# Initialize the interface
interface = outetts.Interface(
    config=outetts.ModelConfig.auto_config(
        model=outetts.Models.VERSION_1_0_SIZE_1B,
        # For llama.cpp backend
        #backend=outetts.Backend.LLAMACPP,
        #quantization=outetts.LlamaCppQuantization.FP16
        # For transformers backend
        backend=outetts.Backend.HF,
    )
)

# Load the default speaker profile
speaker = interface.load_default_speaker("EN-FEMALE-1-NEUTRAL")

app = FastAPI()

@app.get("/")
def greet_json():
    return {"Hello": "World!"}

@app.websocket("/ws/tts")
async def websocket_tts(websocket: WebSocket):
    await websocket.accept()
    try:
        while True:
            # Empfange Text-Chunk vom Client
            data = await websocket.receive_text()
            # Status: Warming up
            await websocket.send_text(json.dumps({"generation_status": "Warming up TTS model"}))
            output = interface.generate(
                config=outetts.GenerationConfig(
                    text=data,
                    generation_type=outetts.GenerationType.CHUNKED,
                    speaker=speaker,
                    sampler_config=outetts.SamplerConfig(
                        temperature=0.4
                    ),
                )
            )
            # Status: Generating linguistic features
            await websocket.send_text(json.dumps({"generation_status": "Generating linguistic features"}))
            # Save to buffer
            import uuid
            temp_path = f"temp_{uuid.uuid4().hex}.wav"
            output.save(temp_path)
            chunk_size = 4096
            try:
                with open(temp_path, "rb") as f:
                    wav_data = f.read()
                    # WAV header is typically 44 bytes, but let's detect it robustly
                    # Find the end of the header (data chunk)
                    if wav_data[:4] != b'RIFF' or wav_data[8:12] != b'WAVE':
                        raise ValueError("Not a valid WAV file")
                    # Find 'data' subchunk
                    data_offset = wav_data.find(b'data')
                    if data_offset == -1:
                        raise ValueError("No 'data' chunk found in WAV file")
                    header_end = data_offset + 8  # 'data' + size (4 bytes)
                    wav_header = bytearray(wav_data[:header_end])
                    pcm_data = wav_data[header_end:]
                    # Patch header: set data length to 0xFFFFFFFF (unknown/streaming)
                    wav_header[data_offset+4:data_offset+8] = (0xFFFFFFFF).to_bytes(4, 'little')
                    # Send header + first PCM chunk
                    first_chunk = pcm_data[:chunk_size]
                    audio_b64 = base64.b64encode(wav_header + first_chunk).decode("ascii")
                    await websocket.send_text(json.dumps({
                        "data": {
                            "audio_bytes": audio_b64,
                            "duration": None,
                            "request_finished": False
                        }
                    }))
                    # Send rest of PCM data in chunks (without header)
                    idx = chunk_size
                    while idx < len(pcm_data):
                        chunk = pcm_data[idx:idx+chunk_size]
                        if not chunk:
                            break
                        audio_b64 = base64.b64encode(chunk).decode("ascii")
                        await websocket.send_text(json.dumps({
                            "data": {
                                "audio_bytes": audio_b64,
                                "duration": None,
                                "request_finished": False
                            }
                        }))
                        idx += chunk_size
            finally:
                try:
                    os.remove(temp_path)
                except FileNotFoundError:
                    pass
            # Final event
            await websocket.send_text(json.dumps({
                "data": {
                    "audio_bytes": "",
                    "duration": None,
                    "request_finished": True
                }
            }))
    except WebSocketDisconnect:
        pass
    except Exception as e:
        await websocket.send_text(json.dumps({"error": str(e)}))