add better title

app.py

@@ -45,15 +45,16 @@ def main():
             else:
                 st.success('Downloaded video')
     
-    if os.path.isfile('audio.mp3'):
+    if os.path.isfile('audio.mp3') and st.session_state.get('latest_video'):
         video_url = st.session_state.get('latest_video', '/')
-        st.write(f"Last downloaded video is: {st.session_state.get('latest_title', '/')} with url {video_url}")
+        video_title = st.session_state.get('latest_title', '/')
+        st.write(f"Last downloaded video is: {video_title} with url {video_url}")
         st.audio('audio.mp3')
         buffer = BytesIO()
         with open('audio.mp3', 'rb') as f:
             buffer.write(f.read())
         timestamp = datetime.now().strftime('%Y-%m-%d_%H-%M-%S')
-        st.download_button(label='Download mp3', data=buffer.getvalue(), file_name=f'audio_{timestamp}.mp3', mime='audio/mp3')
+        st.download_button(label='Download mp3', data=buffer.getvalue(), file_name=f"{video_title.replace(' ', '-')}.mp3', mime='audio/mp3")
 
 if __name__ == '__main__':
     main()