diff --git a/infer/lib/audio.py b/infer/lib/audio.py
index 89799ab..e406ab8 100644
--- a/infer/lib/audio.py
+++ b/infer/lib/audio.py
@@ -1,18 +1,24 @@
-import platform
+from io import BufferedWriter, BytesIO
+from pathlib import Path
+from typing import Dict
 import ffmpeg
 import numpy as np
 import av
 
+video_format_dict: Dict[str, str] = {
+    "m4a": "mp4",
+}
 
-def wav2(i, o, format):
+audio_format_dict: Dict[str, str] = {
+    "ogg": "libvorbis",
+    "mp4": "aac",
+}
+
+def wav2(i: BytesIO, o: BufferedWriter, format: str):
     inp = av.open(i, "r")
-    if format == "m4a":
-        format = "mp4"
+    format = video_format_dict.get(format, format)
     out = av.open(o, "w", format=format)
-    if format == "ogg":
-        format = "libvorbis"
-    if format == "mp4":
-        format = "aac"
+    format = audio_format_dict.get(format, format)
 
     ostream = out.add_stream(format)
 
@@ -27,12 +33,15 @@ def wav2(i, o, format):
     inp.close()
 
 
-def load_audio(file, sr):
+def load_audio(file: str, sr: int) -> np.ndarray:
+    if not Path(file).exists():
+        raise FileNotFoundError(f"File not found: {file}")
+
     try:
         # https://github.com/openai/whisper/blob/main/whisper/audio.py#L26
         # This launches a subprocess to decode audio while down-mixing and resampling as necessary.
         # Requires the ffmpeg CLI and `ffmpeg-python` package to be installed.
-        file = clean_path(file)  # 防止小白拷路径头尾带了空格和"和回车
+        file = str(clean_path(file))  # 防止小白拷路径头尾带了空格和"和回车
         out, _ = (
             ffmpeg.input(file, threads=0)
             .output("-", format="f32le", acodec="pcm_f32le", ac=1, ar=sr)
@@ -44,7 +53,5 @@ def load_audio(file, sr):
     return np.frombuffer(out, np.float32).flatten()
 
 
-def clean_path(path_str):
-    if platform.system() == "Windows":
-        path_str = path_str.replace("/", "\\")
-    return path_str.strip(" ").strip('"').strip("\n").strip('"').strip(" ")
+def clean_path(path: str) -> Path:
+    return Path(path.strip(' "\n')).resolve()