ffmpeg scale doesn't work if destination res is larger than source

Question

I just tried ffmpeg filter scale=320x180:force_original_aspect_ratio=disable to resize a 270x480 video into a 320x180 video, and it still keeps aspect ratio. force_original_aspect_ratio=disable got ignored.

I guess the problem is that the destination width is bigger than the source width, while the destination height is smaller. Because it worked for other videos, even without force_original_aspect_ratio=disable.

The resulted file is also weird. It says it's 320x180, while its weight is obliviously smaller than that.

Here are the video files, original and resized. https://drive.google.com/file/d/1UNXlfwpzoizhx7WOjqn44mlcbQgacOHS/view?usp=sharing

Here is my command:

ffmpeg -i 480P_600K_107047752.mp4 -force_key_frames 00:00:03.000 -filter_complex [0:v]scale=320x180:force_original_aspect_ratio=disable,fps=30[vid];[vid]

Answer 1

Modify first filterchain to

scale=320x180,setsar=1,fps=30