app.py

import io
import re
import wave
import struct

import numpy as np
import torch
from fastapi import FastAPI, HTTPException
from fastapi.responses import StreamingResponse, Response, HTMLResponse
from fastapi.middleware import Middleware
from fastapi.middleware.gzip import GZipMiddleware

from misaki import en

import os
import numpy as np
from onnxruntime import InferenceSession
from huggingface_hub import snapshot_download

import json

# Load the configuration file
config_file_path = 'config.json'  # Update this with the path to your config file

with open(config_file_path, 'r') as f:
    config = json.load(f)

# Extract the phoneme vocabulary
phoneme_vocab = config['vocab']

# Step 3: Download the model and voice file from Hugging Face Hub
model_repo = "onnx-community/Kokoro-82M-v1.0-ONNX"
model_name = "onnx/model_q8f16.onnx"
voice_file = "voices"
local_dir = "."

# Download the model and voice file
snapshot_download(
    repo_id=model_repo,
    local_dir=local_dir,
    allow_patterns=[model_name, voice_file],
)

# Step 4: Load the model
model_path = os.path.join(local_dir, model_name)
sess = InferenceSession(model_path)

app = FastAPI(
    title="Kokoro TTS FastAPI",
    middleware=[
        Middleware(GZipMiddleware, compresslevel=9)  # Add GZip compression
    ]
)

# ------------------------------------------------------------------------------
# Global Pipeline Instance
# ------------------------------------------------------------------------------
# Create one pipeline instance for the entire app.



# ------------------------------------------------------------------------------
# Helper Functions
# ------------------------------------------------------------------------------

def generate_wav_header(sample_rate: int, num_channels: int, sample_width: int, data_size: int = 0x7FFFFFFF) -> bytes:
    """
    Generate a WAV header for streaming.
    Since we don't know the final audio size, we set the data chunk size to a large dummy value.
    This header is sent only once at the start of the stream.
    """
    bits_per_sample = sample_width * 8
    byte_rate = sample_rate * num_channels * sample_width
    block_align = num_channels * sample_width
    # total file size = 36 + data_size (header is 44 bytes total)
    total_size = 36 + data_size
    header = struct.pack('<4sI4s', b'RIFF', total_size, b'WAVE')
    fmt_chunk = struct.pack('<4sIHHIIHH', b'fmt ', 16, 1, num_channels, sample_rate, byte_rate, block_align, bits_per_sample)
    data_chunk_header = struct.pack('<4sI', b'data', data_size)
    return header + fmt_chunk + data_chunk_header


def custom_split_text(text: str) -> list:
    """
    Custom splitting:
      - Start with a chunk size of 2 words.
      - For each chunk, if a period (".") is found in any word (except if it’s the very last word),
        then split the chunk at that word (include words up to that word).
      - Otherwise, use the current chunk size.
      - For subsequent chunks, increase the chunk size by 2.
      - If there are fewer than the desired number of words for a full chunk, add all remaining words.
    """
    words = text.split()
    chunks = []
    chunk_size = 2
    start = 0
    while start < len(words):
        candidate_end = start + chunk_size
        if candidate_end > len(words):
            candidate_end = len(words)
        chunk_words = words[start:candidate_end]
        # Look for a period in any word except the last one.
        split_index = None
        for i in range(len(chunk_words) - 1):
            if '.' in chunk_words[i]:
                split_index = i
                break
        if split_index is not None:
            candidate_end = start + split_index + 1
            chunk_words = words[start:candidate_end]
        chunks.append(" ".join(chunk_words))
        start = candidate_end
        chunk_size += 2  # Increase the chunk size by 2 for the next iteration.
    return chunks


def audio_tensor_to_pcm_bytes(audio_tensor: torch.Tensor) -> bytes:
    """
    Convert a torch.FloatTensor (with values in [-1, 1]) to raw 16-bit PCM bytes.
    """
    # Ensure tensor is on CPU and flatten if necessary.
    audio_np = audio_tensor.cpu().numpy()
    if audio_np.ndim > 1:
        audio_np = audio_np.flatten()
    # Scale to int16 range.
    audio_int16 = np.int16(audio_np * 32767)
    return audio_int16.tobytes()


def audio_tensor_to_opus_bytes(audio_tensor: torch.Tensor, sample_rate: int = 24000, bitrate: int = 32000) -> bytes:
    """
    Convert a torch.FloatTensor to Opus encoded bytes.
    Requires the 'opuslib' package: pip install opuslib
    """
    try:
        import opuslib
    except ImportError:
        raise ImportError("opuslib is not installed. Please install it with: pip install opuslib")

    audio_np = audio_tensor.cpu().numpy()
    if audio_np.ndim > 1:
        audio_np = audio_np.flatten()
    # Scale to int16 range.  Important for opus.
    audio_int16 = np.int16(audio_np * 32767)

    encoder = opuslib.Encoder(sample_rate, 1, opuslib.APPLICATION_VOIP) # 1 channel for mono.

    # Calculate the number of frames to encode. Opus frames are 2.5, 5, 10, or 20 ms long.
    frame_size = int(sample_rate * 0.020)  # 20ms frame size

    encoded_data = b''
    for i in range(0, len(audio_int16), frame_size):
        frame = audio_int16[i:i + frame_size]
        if len(frame) < frame_size:
            # Pad the last frame with zeros if needed.
            frame = np.pad(frame, (0, frame_size - len(frame)), 'constant')
        encoded_frame = encoder.encode(frame.tobytes(), frame_size) # Encode the frame.
        encoded_data += encoded_frame

    return encoded_data

g2p = en.G2P(trf=False, british=False, fallback=None) # no transformer, American English

def tokenizer(text):
    phonemes_string, _ = g2p(text)
    phonemes = []
    for i in phonemes_string:
        phonemes.append(i)
    tokens = [phoneme_vocab[phoneme] for phoneme in phonemes if phoneme in phoneme_vocab]
    return tokens
    
    


# ------------------------------------------------------------------------------
# Endpoints
# ------------------------------------------------------------------------------

# @app.get("/tts/streaming", summary="Streaming TTS")
# def tts_streaming(text: str, voice: str = "af_heart", speed: float = 1.0, format: str = "opus"):
#     """
#     Streaming TTS endpoint that returns a continuous audio stream.
#     Supports WAV (PCM) and Opus formats.  Opus offers significantly better compression.

#     The endpoint first yields a WAV header (with a dummy length) for WAV,
#     then yields encoded audio data for each text chunk as soon as it is generated.
#     """
#     # Split the input text using the custom doubling strategy.
#     chunks = custom_split_text(text)
#     sample_rate = 24000
#     num_channels = 1
#     sample_width = 2  # 16-bit PCM


#     def audio_generator():
#         if format.lower() == "wav":
#             # Yield the WAV header first.
#             header = generate_wav_header(sample_rate, num_channels, sample_width)
#             yield header
#         # Process and yield each chunk's audio data.
#         for i, chunk in enumerate(chunks):
#             print(f"Processing chunk {i}: {chunk}")  # Debugging
#             try:
#                 results = list(pipeline(chunk, voice=voice, speed=speed, split_pattern=None))
#                 for result in results:
#                     if result.audio is not None:
#                         if format.lower() == "wav":
#                             yield audio_tensor_to_pcm_bytes(result.audio)
#                         elif format.lower() == "opus":
#                             yield audio_tensor_to_opus_bytes(result.audio, sample_rate=sample_rate)
#                         else:
#                             raise ValueError(f"Unsupported audio format: {format}")
#                     else:
#                         print(f"Chunk {i}: No audio generated")
#             except Exception as e:
#                 print(f"Error processing chunk {i}: {e}")
#                 yield b'' # important so that streaming continues.  Consider returning an error sound.

#     media_type = "audio/wav" if format.lower() == "wav" else "audio/opus"

#     return StreamingResponse(
#         audio_generator(),
#         media_type=media_type,
#         headers={"Cache-Control": "no-cache"},
#     )


@app.get("/tts/full", summary="Full TTS")
def tts_full(text: str, voice: str = "af_heart", speed: float = 1.0, format: str = "wav"):
    """
    Full TTS endpoint that synthesizes the entire text, concatenates the audio,
    and returns a complete WAV or Opus file.
    """
    voice_path = os.path.join(local_dir, f"voices/{voice}.bin")    
    voices = np.fromfile(voice_path, dtype=np.float32).reshape(-1, 1, 256)

    tokens = tokenizer(text)

    final_token = [[0, *tokens]]

    full_audio = sess.run(None, dict(
        input_ids=tokens,
        style=ref_s,
        speed=np.ones(1, dtype=np.float32),
    ))[0]

    # Write the concatenated audio to an in-memory WAV or Opus file.
    sample_rate = 24000
    num_channels = 1
    sample_width = 2  # 16-bit PCM -> 2 bytes per sample
    if format.lower() == "wav":
        wav_io = io.BytesIO()
        with wave.open(wav_io, "wb") as wav_file:
            wav_file.setnchannels(num_channels)
            wav_file.setsampwidth(sample_width)
            wav_file.setframerate(sample_rate)
            full_audio_int16 = np.int16(full_audio * 32767)
            wav_file.writeframes(full_audio_int16.tobytes())
        wav_io.seek(0)
        return Response(content=wav_io.read(), media_type="audio/wav")
    elif format.lower() == "opus":
        opus_data = audio_tensor_to_opus_bytes(torch.from_numpy(full_audio), sample_rate=sample_rate)
        return Response(content=opus_data, media_type="audio/opus")
    else:
        raise HTTPException(status_code=400, detail=f"Unsupported audio format: {format}")



@app.get("/", response_class=HTMLResponse)
def index():
    """
    HTML demo page for Kokoro TTS.

    This page provides a simple UI to enter text, choose a voice and speed,
    and play synthesized audio from both the streaming and full endpoints.
    """
    return """
    <!DOCTYPE html>
    <html>
    <head>
        <title>Kokoro TTS Demo</title>
    </head>
    <body>
        <h1>Kokoro TTS Demo</h1>
        <textarea id="text" rows="4" cols="50" placeholder="Enter text here"></textarea><br>
        <label for="voice">Voice:</label>
        <input type="text" id="voice" value="af_heart"><br>
        <label for="speed">Speed:</label>
        <input type="number" step="0.1" id="speed" value="1.0"><br>
        <label for="format">Format:</label>
        <select id="format">
            <option value="wav">WAV</option>
            <option value="opus" selected>Opus</option>
        </select><br><br>
        <button onclick="playStreaming()">Play Streaming TTS</button>
        <button onclick="playFull()">Play Full TTS</button>
        <br><br>
        <audio id="audio" controls autoplay></audio>
        <script>
            function playStreaming() {
                const text = document.getElementById('text').value;
                const voice = document.getElementById('voice').value;
                const speed = document.getElementById('speed').value;
                const format = document.getElementById('format').value;
                const audio = document.getElementById('audio');
                // Set the audio element's source to the streaming endpoint.
                audio.src = `/tts/streaming?text=${encodeURIComponent(text)}&voice=${encodeURIComponent(voice)}&speed=${speed}&format=${format}`;
                audio.type = format === 'wav' ? 'audio/wav' : 'audio/opus';
                audio.play();
            }
            function playFull() {
                const text = document.getElementById('text').value;
                const voice = document.getElementById('voice').value;
                const speed = document.getElementById('speed').value;
                const format = document.getElementById('format').value;
                const audio = document.getElementById('audio');
                // Set the audio element's source to the full TTS endpoint.
                audio.src = `/tts/full?text=${encodeURIComponent(text)}&voice=${encodeURIComponent(voice)}&speed=${speed}&format=${format}`;
                audio.type = format === 'wav' ? 'audio/wav' : 'audio/opus';
                audio.play();
            }
        </script>
    </body>
    </html>
    """


# ------------------------------------------------------------------------------
# Run with: uvicorn app:app --reload
# ------------------------------------------------------------------------------
if __name__ == "__main__":
    import uvicorn

    uvicorn.run("app:app", host="0.0.0.0", port=7860, reload=True)