# The right way to calculate 1080p 720p 360p 240p quality

ffmpegresolutionvideo

I'm working on a video hosting project and I would like to know if I'm converting my videos quality the right way.

my equation is: newY=(y/x)*newX

so 1080p is:

    1080x460
than 720p
720x306
...
480x204
360x154
240x102
144x60


My problem is 360 and below comes out in a terrible quality. comparing that to youtube I'm wondering if they are actually changing the video resolution or just changing the kb/s?