add file validation

app.py

@@ -317,6 +317,8 @@ def main(file, name, fps=30, res: tuple=(1280,720), oscres=512, sr=11025, lyrics
 def gradio_interface(audio_file, lyrics, output_name, fps=30, vidwidth=1280, vidheight=720, oscres=512, img=None, tit=None, ast=None):
     if audio_file is None:
         raise gr.Error("Please Provide an Audio File")
+    if not str(audio_file).endswith(".mp3"):
+        raise gr.Error("Only MP3 Files are supported at this time")
 
     resolution = f"{vidwidth}x{vidheight}"
     res = tuple(map(int, resolution.split('x')))