diff --git a/app/services/subtitle.py b/app/services/subtitle.py
index f86db9d..e62ce57 100644
--- a/app/services/subtitle.py
+++ b/app/services/subtitle.py
@@ -11,12 +11,15 @@ from app.utils import utils
 model_size = config.whisper.get("model_size", "large-v3")
 device = config.whisper.get("device", "cpu")
 compute_type = config.whisper.get("compute_type", "int8")
-
-if config.app.get("subtitle_provider") == "whisper":
-    model = WhisperModel(model_size_or_path=model_size, device=device, compute_type=compute_type)
+model = None
 
 
 def create(audio_file, subtitle_file: str = ""):
+    global model
+    if not model:
+        logger.info(f"loading model: {model_size}, device: {device}, compute_type: {compute_type}")
+        model = WhisperModel(model_size_or_path=model_size, device=device, compute_type=compute_type)
+
     logger.info(f"start, output file: {subtitle_file}")
     if not subtitle_file:
         subtitle_file = f"{audio_file}.srt"
diff --git a/app/services/task.py b/app/services/task.py
index 079556b..1961608 100644
--- a/app/services/task.py
+++ b/app/services/task.py
@@ -1,3 +1,4 @@
+import os.path
 from os import path
 
 from loguru import logger
@@ -64,9 +65,14 @@ def start(task_id, params: VideoParams):
 
     subtitle_provider = config.app.get("subtitle_provider", "").strip().lower()
     logger.info(f"\n\n## generating subtitle, provider: {subtitle_provider}")
+    subtitle_fallback = False
     if subtitle_provider == "edge":
         voice.create_subtitle(text=script, sub_maker=sub_maker, subtitle_file=subtitle_path)
-    if subtitle_provider == "whisper":
+        if not os.path.exists(subtitle_path):
+            subtitle_fallback = True
+            logger.warning("subtitle file not found, fallback to whisper")
+
+    if subtitle_provider == "whisper" or subtitle_fallback:
         subtitle.create(audio_file=audio_file, subtitle_file=subtitle_path)
         logger.info("\n\n## correcting subtitle")
         subtitle.correct(subtitle_file=subtitle_path, video_script=script)