Video is squished on using aspect ratios other than 1920x1080 or 16:9.

I want to render manim animations on a different aspect ratio instead of the default. So, I pass these values to the class.

```
class diffResolution(Scene):
CONFIG={
"camera_config":{"background_color": '#ffffff', "pixel_width": 1080, "pixel_height": 1920}
}
```

and

```
class diffResolution(Scene):
CONFIG={
"frame_config":{"frame_shape": (9, 16)}
}
```

However, the contents of the video still don't maintain the new aspect ratio. I run the following command in terminal.

```
manimgl example.py diffResolution -o -r 1080x1920
```

How can I get the video to display without any stretching in manim?

Thanks. :)