app.py

import spaces
import gradio as gr
import torch
import soundfile as sf
from transformers import AutoTokenizer, AutoModelForCausalLM
from xcodec2.modeling_xcodec2 import XCodec2Model
import tempfile

device = "cuda" if torch.cuda.is_available() else "cpu"
####################
#  Global model loading
####################
model_name = "fakeavatar/vtubers-4"
print("Loading tokenizer & model ...")
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(model_name)
model.eval().to(device)

print("Loading XCodec2Model ...")
codec_model_path = "HKUSTAudio/xcodec2"
Codec_model = XCodec2Model.from_pretrained(codec_model_path)
Codec_model.eval().to(device)

print("Models loaded.")

####################
#  Inference function
####################
def extract_speech_ids(speech_tokens_str):
    """
    Restore an integer 23456 from tokens like <|s_23456|>
    """
    speech_ids = []
    for token_str in speech_tokens_str:
        if token_str.startswith("<|s_") and token_str.endswith("|>"):
            num_str = token_str[4:-2]
            num = int(num_str)
            speech_ids.append(num)
        else:
            print(f"Unexpected token: {token_str}")
    return speech_ids

@spaces.GPU
def text2speech(input_text, num_samples):


    """
    Convert text to speech waveform and return the audio file path
    """
    results = []
    with torch.no_grad():
        for i in range(0, num_samples):

            # Add start and end tokens around the input text
            formatted_text = f"<|TEXT_UNDERSTANDING_START|>{input_text}<|TEXT_UNDERSTANDING_END|>"
            chat = [
                {"role": "user", "content": "Convert the text to speech:" + formatted_text},
                {"role": "assistant", "content": f"<|SPEECH_GENERATION_START|>"}
            ]

            # tokenizer.apply_chat_template is used in the Llasa-style dialogue model
            input_ids = tokenizer.apply_chat_template(
                chat,
                tokenize=True,
                return_tensors='pt',
                continue_final_message=True
            ).to(device)

            # End token
            speech_end_id = tokenizer.convert_tokens_to_ids("<|SPEECH_GENERATION_END|>")

            # Text generation
            outputs = model.generate(
                input_ids,
                max_length=2048,  # We trained our model with a max length of 2048
                eos_token_id=speech_end_id,
                do_sample=True,
                top_p=0.95,           # Adjusts the diversity of generated content
                temperature=0.9,   # Controls randomness in output
                repetition_penalty=1.2,
            )

            # Extract newly generated tokens (excluding the input part)
            generated_ids = outputs[0][input_ids.shape[1]:-1]
            speech_tokens_str = tokenizer.batch_decode(generated_ids, skip_special_tokens=True)

            # Extract <|s_23456|> as [23456 ...]
            speech_tokens_int = extract_speech_ids(speech_tokens_str)
            speech_tokens_int = torch.tensor(speech_tokens_int).to(device).unsqueeze(0).unsqueeze(0)

            # Decode waveform using XCodec2Model
            gen_wav = Codec_model.decode_code(speech_tokens_int)  # [batch, channels, samples]

            # Get audio data and sample rate
            audio = gen_wav[0, 0, :].cpu().numpy()
            sample_rate = 16000

            # Save the audio to a temporary file
            with tempfile.NamedTemporaryFile(suffix=".wav", delete=False) as tmpfile:
                sf.write(tmpfile.name, audio, sample_rate)
                audio_path = tmpfile.name

            results.append(audio_path)
    while len(results) < 10:
        results.append(results[-1])
    return results

####################
#  Gradio Interface
####################

# Slider to control the number of audio samples to generate
num_samples_slider = gr.Slider(minimum=1, maximum=10, value=4, step=1, label="Number of Audio Samples")
demo = gr.Interface(
    fn=text2speech,
    inputs=[gr.Textbox(label="Enter text", lines=5), num_samples_slider],
    outputs=[gr.Audio(label=f"Generated Audio {i+1}", type="numpy") for i in range(10)],
    title="VTuber TTS",
    description="Input a piece of text in English,  and click to generate speech."
)

if __name__ == "__main__":
    demo.launch(
    share=True )