diff --git a/whisperx/transcribe.py b/whisperx/transcribe.py
index 4432abe..691e3f9 100644
--- a/whisperx/transcribe.py
+++ b/whisperx/transcribe.py
@@ -21,7 +21,7 @@ def cli():
     parser.add_argument("--model", default="small", help="name of the Whisper model to use")
     parser.add_argument("--model_dir", type=str, default=None, help="the path to save model files; uses ~/.cache/whisper by default")
     parser.add_argument("--device", default="cuda" if torch.cuda.is_available() else "cpu", help="device to use for PyTorch inference")
-    parser.add_argument("--device_index", default=None, type=int, help="device index to use for FasterWhisper inference")
+    parser.add_argument("--device_index", default=0, type=int, help="device index to use for FasterWhisper inference")
     parser.add_argument("--batch_size", default=8, type=int, help="device to use for PyTorch inference")
     parser.add_argument("--compute_type", default="float16", type=str, choices=["float16", "float32", "int8"], help="compute type for computation")