How to save result to an mp4 file?

After your example code...

```
from video_kandinsky3 import get_T2V_pipeline

t2v_pipe = get_T2V_pipeline('cuda', fp16=True)

pfps = 'medium' # ['low', 'medium', 'high']
video = t2v_pipe(
'a red car is drifting on the mountain road, close view, fast movement',
width=640, height=384, fps=fps
)
```

how do I save the video to an mp4 file?

Also what is the recommended fps to use?