If each frame in the media contains the exact 1920 × 1080 pixels ...
This image has the same number of pixels on the top and bottom half, but you can probably see the bottom half looks worse. That's what lower bitrate does. It's like turning up the compression on a jpg -- you are not getting the exact same pixels, just the exact same image size.
This image has the same number of pixels on the top and bottom half, but you can probably see the bottom half looks worse. That's what lower bitrate does. It's like turning up the compression on a jpg -- you are not getting the exact same pixels, just the exact same image size.
https://i.imgur.com/CFriCXf.png