diff --git a/app.py b/app.py
index 742dfd7..7d5c7b3 100644
--- a/app.py
+++ b/app.py
@@ -1,4 +1,5 @@
 import os
+from subprocess import check_call, CalledProcessError
 from flask import Flask
 
 from flask import request, render_template
@@ -12,6 +13,21 @@ app = Flask(
 os.makedirs("uploads", exist_ok=True)
 
 
+def convert_to_wav(file_name: str):
+    assert file_name.endswith(".wav")
+    output, extension = file_name.rsplit(".", maxsplit=1)
+
+    assert extension != "wav"
+
+    print(f"{extension=}")
+    command = f"tape2wav {file_name} ${output}.wav"
+    try:
+        check_call(command.split())
+    except CalledProcessError as exc:
+        print(f"tape2wav failed: {exc.output=}\n{exc.stderr=}")
+        raise
+
+
 @app.route("/")
 def upload_form():
     return render_template(
@@ -40,6 +56,12 @@ def upload_file():
     except Exception as exc:
         return f"fail: {exc=}"
 
+    name, extension = file.filename.rsplit(".", maxsplit=1)
+    if extension != "wav":
+        thread = Thread(target=convert_to_wav, args=(file.filename,))
+        thread.start()
+        print(f"thread started for {file.filename=}")
+
     return "File uploaded successfully"