attempt 5 at fps issue

app.py

@@ -38,7 +38,7 @@ def extract_waveform_animation(audio_file, window_seconds=5):
         line.set_data(x_vals[start:end], window)
         return line,
 
-    total_frames = int(duration)
+    total_frames = int(duration) * FPS
     ani = FuncAnimation(fig, update, frames=range(total_frames), 
                        init_func=init, interval=window_seconds*FPS, blit=False)