Enable MPS GPU Accerlation on MacOS (#164)

* Enable MPS GPU Accerlation on MacOS

* Fix

README.md

@@ -95,6 +95,14 @@ To install espeak-ng on Windows:
 
 For advanced configuration and usage on Windows, see the [official espeak-ng Windows guide](https://github.com/espeak-ng/espeak-ng/blob/master/docs/guide.md)
 
+### MacOS Apple Silicon GPU Acceleration
+
+On Mac M1/M2/M3/M4 devices, you can explicitly specify the environment variable `PYTORCH_ENABLE_MPS_FALLBACK=1` to enable GPU acceleration.
+
+```bash
+PYTORCH_ENABLE_MPS_FALLBACK=1 python run-your-kokoro-script.py
+```
+
 ### Conda Environment
 Use the following conda `environment.yml` if you're facing any dependency issues.
 ```yaml

kokoro/pipeline.py

@@ -6,6 +6,7 @@ from misaki import en, espeak
 from typing import Callable, Generator, List, Optional, Tuple, Union
 import re
 import torch
+import os
 
 ALIASES = {
     'en-us': 'a',
@@ -93,8 +94,17 @@ class KPipeline:
         elif model:
             if device == 'cuda' and not torch.cuda.is_available():
                 raise RuntimeError("CUDA requested but not available")
+            if device == 'mps' and not torch.backends.mps.is_available():
+                raise RuntimeError("MPS requested but not available")
+            if device == 'mps' and os.environ.get('PYTORCH_ENABLE_MPS_FALLBACK') != '1':
+                raise RuntimeError("MPS requested but fallback not enabled")
             if device is None:
-                device = 'cuda' if torch.cuda.is_available() else 'cpu'
+                if torch.cuda.is_available():
+                    device = 'cuda'
+                elif os.environ.get('PYTORCH_ENABLE_MPS_FALLBACK') == '1' and torch.backends.mps.is_available():
+                    device = 'mps'
+                else:
+                    device = 'cpu'
             try:
                 self.model = KModel(repo_id=repo_id).to(device).eval()
             except RuntimeError as e: