Refactored Code

app.py

@@ -1,7 +1,7 @@
 import random
 import numpy as np
 import torch
-from chatterbox.src.chatterbox.tts import ChatterboxTTS # Assuming this path is correct
+from chatterbox.src.chatterbox.tts import ChatterboxTTS
 import gradio as gr
 import spaces
 
@@ -9,38 +9,32 @@ DEVICE = "cuda" if torch.cuda.is_available() else "cpu"
 print(f"🚀 Running on device: {DEVICE}")
 
 # --- Global Model Initialization ---
-# Load the model once when the application starts.
-# This model will be accessible by the @spaces.GPU decorated function.
 MODEL = None
 
 def get_or_load_model():
+    """Loads the ChatterboxTTS model if it hasn't been loaded already,
+    and ensures it's on the correct device."""
     global MODEL
     if MODEL is None:
-        print("Global MODEL is None, loading...")
+        print("Model not loaded, initializing...")
         try:
             MODEL = ChatterboxTTS.from_pretrained(DEVICE)
-            # Ensure model is on the correct device if not handled by from_pretrained
-            if DEVICE == "cuda" and hasattr(MODEL, 'to'):
+            if hasattr(MODEL, 'to') and str(MODEL.device) != DEVICE:
                 MODEL.to(DEVICE)
-            print(f"Global MODEL loaded. Device: {DEVICE}")
-            if hasattr(MODEL, 'device'): # If the model object has a device attribute
-                 print(f"Model internal device attribute: {MODEL.device}")
+            print(f"Model loaded successfully. Internal device: {getattr(MODEL, 'device', 'N/A')}")
         except Exception as e:
-            print(f"Error loading global model: {e}")
+            print(f"Error loading model: {e}")
             raise
     return MODEL
 
 # Attempt to load the model at startup.
-# If this fails, the app will likely fail to start, which is informative.
 try:
     get_or_load_model()
 except Exception as e:
-    # Handle critical model loading failure if necessary, or let it propagate
-    print(f"CRITICAL: Failed to load model on startup. Error: {e}")
-    # You might want to display an error in Gradio if this happens,
-    # but for now, a print is fine for debugging.
+    print(f"CRITICAL: Failed to load model on startup. Application may not function. Error: {e}")
 
 def set_seed(seed: int):
+    """Sets the random seed for reproducibility across torch, numpy, and random."""
     torch.manual_seed(seed)
     if DEVICE == "cuda":
         torch.cuda.manual_seed(seed)
@@ -48,46 +42,78 @@ def set_seed(seed: int):
     random.seed(seed)
     np.random.seed(seed)
 
-@spaces.GPU # Your GPU-accelerated function
-def generate_tts_audio(text_input, audio_prompt_path_input, exaggeration_input, temperature_input, seed_num_input, cfgw_input):
-    current_model = get_or_load_model() # Access the global model
+@spaces.GPU
+def generate_tts_audio(
+    text_input: str,
+    audio_prompt_path_input: str,
+    exaggeration_input: float,
+    temperature_input: float,
+    seed_num_input: int,
+    cfgw_input: float
+) -> tuple[int, np.ndarray]:
+    """
+    Generates TTS audio using the ChatterboxTTS model.
+
+    Args:
+        text_input: The text to synthesize (max 300 characters).
+        audio_prompt_path_input: Path to the reference audio file.
+        exaggeration_input: Exaggeration parameter for the model.
+        temperature_input: Temperature parameter for the model.
+        seed_num_input: Random seed (0 for random).
+        cfgw_input: CFG/Pace weight.
+
+    Returns:
+        A tuple containing the sample rate (int) and the audio waveform (numpy.ndarray).
+    """
+    current_model = get_or_load_model()
 
     if current_model is None:
-        # This should ideally not happen if startup loading was successful
-        # Or, it indicates an issue with the global model pattern in this specific env.
-        raise RuntimeError("Model could not be loaded or accessed.")
+        raise RuntimeError("TTS model is not loaded.")
 
     if seed_num_input != 0:
         set_seed(int(seed_num_input))
 
-    print(f"Generating audio for text: '{text_input}'")
+    print(f"Generating audio for text: '{text_input[:50]}...'")
     wav = current_model.generate(
-        text_input[:300],
+        text_input[:300],  # Truncate text to max chars
         audio_prompt_path=audio_prompt_path_input,
         exaggeration=exaggeration_input,
         temperature=temperature_input,
         cfg_weight=cfgw_input,
     )
     print("Audio generation complete.")
-    # ONLY return pickleable data
     return (current_model.sr, wav.squeeze(0).numpy())
 
-
 with gr.Blocks() as demo:
-    # No gr.State needed for the model object if it's managed globally
-    # and not passed back and forth.
-
+    gr.Markdown(
+        """
+        # Chatterbox TTS Demo
+        Generate high-quality speech from text with reference audio styling.
+        """
+    )
     with gr.Row():
         with gr.Column():
-            text = gr.Textbox(value="Now let's make my mum's favourite. So three mars bars into the pan. Then we add the tuna and just stir for a bit, just let the chocolate and fish infuse. A sprinkle of olive oil and some tomato ketchup. Now smell that. Oh boy this is going to be incredible.", label="Text to synthesize (max chars 300)")
-            ref_wav = gr.Audio(sources=["upload", "microphone"], type="filepath", label="Reference Audio File", value="https://storage.googleapis.com/chatterbox-demo-samples/prompts/female_shadowheart.flac")
-            exaggeration = gr.Slider(0.25, 2, step=.05, label="Exaggeration (Neutral = 0.5, extreme values can be unstable)", value=.5)
-            cfg_weight = gr.Slider(0.2, 1, step=.05, label="CFG/Pace", value=0.5)
+            text = gr.Textbox(
+                value="Now let's make my mum's favourite. So three mars bars into the pan. Then we add the tuna and just stir for a bit, just let the chocolate and fish infuse. A sprinkle of olive oil and some tomato ketchup. Now smell that. Oh boy this is going to be incredible.",
+                label="Text to synthesize (max chars 300)",
+                max_lines=5
+            )
+            ref_wav = gr.Audio(
+                sources=["upload", "microphone"],
+                type="filepath",
+                label="Reference Audio File (Optional)",
+                value="https://storage.googleapis.com/chatterbox-demo-samples/prompts/female_shadowheart.flac"
+            )
+            exaggeration = gr.Slider(
+                0.25, 2, step=.05, label="Exaggeration (Neutral = 0.5, extreme values can be unstable)", value=.5
+            )
+            cfg_weight = gr.Slider(
+                0.2, 1, step=.05, label="CFG/Pace", value=0.5
+            )
 
             with gr.Accordion("More options", open=False):
                 seed_num = gr.Number(value=0, label="Random seed (0 for random)")
-                temp = gr.Slider(0.05, 5, step=.05, label="temperature", value=.8)
-
+                temp = gr.Slider(0.05, 5, step=.05, label="Temperature", value=.8)
 
             run_btn = gr.Button("Generate", variant="primary")
 
@@ -95,9 +121,8 @@ with gr.Blocks() as demo:
             audio_output = gr.Audio(label="Output Audio")
 
     run_btn.click(
-        fn=generate_tts_audio, # Use the new function name
+        fn=generate_tts_audio,
         inputs=[
-            # model_state, # Removed: model is now global
             text,
             ref_wav,
             exaggeration,
@@ -105,10 +130,7 @@ with gr.Blocks() as demo:
             seed_num,
             cfg_weight,
         ],
-        outputs=[audio_output], # Only outputting the audio data
+        outputs=[audio_output],
     )
 
-demo.queue(
-    max_size=50,
-    default_concurrency_limit=1, # Important for a single global model
-).launch() # share=True is not needed and causes a warning on Spaces
+demo.launch()