attempt 4 at fps issue

app.py

@@ -12,7 +12,7 @@ def extract_waveform_animation(audio_file, window_seconds=5):
     FPS = 30
     fig, ax = plt.subplots()
     line, = ax.plot([], [], lw=2)
-    window_length = int(window_seconds * sr / FPS)
+    window_length = int(window_seconds * sr * FPS)
     
     # Initialize with first window
     first_window = y[:window_length]
@@ -40,7 +40,7 @@ def extract_waveform_animation(audio_file, window_seconds=5):
 
     total_frames = int(duration)
     ani = FuncAnimation(fig, update, frames=range(total_frames), 
-                       init_func=init, interval=window_seconds, blit=False)
+                       init_func=init, interval=window_seconds*FPS, blit=False)
     
     with tempfile.NamedTemporaryFile(delete=False, suffix='.mp4') as tmpfile:
         ani.save(tmpfile.name, writer='ffmpeg', fps=FPS)