before we start never ever upscale for example your source is just 480p and you want it 720p that is wrong thinking, you will only make the video blurry

ok back to the main guide if your wandering how to get properly the resize resolution of a source video here is the simple way

for example you got a source of 1280×960

then lets say you want to downsize to 576p:

1280 = 960

x = 576

then cross multiply:

x960 = 737280

x = 768

so its:

768×576

to check:

1280/960 = 1.333

768/576 = 1.333

1.333 = 1.333

so your 576p resolution is 768×576

for example you got a source of 1280×720

then lets say you want to downsize to 400p

1280 = 720

x = 400

then cross multiply:

x720 = 512000

x = 711

so its:

711×400

to check:

1280/720 = 1.77

711×400 = 1.77

1.77 = 1.77

so your 400p resolution is 711×400

for example you got a source of 1280×720

then lets say you want to downsize to 480p

1280 = 720

x = 480

then cross multiply:

x720 = 614400

x = 853

so its:

853×480

to check:

1280/720 = 1.77

853/480 = 1.77

1.77 = 1.77

so your 480p resolution is 853×480

thats it you got it now

then lets say you want to downsize to 576p:

1280 = 960

x = 576

then cross multiply:

x960 = 737280

x = 768

so its:

768×576

to check:

1280/960 = 1.333

768/576 = 1.333

1.333 = 1.333

so your 576p resolution is 768×576

for example you got a source of 1280×720

then lets say you want to downsize to 400p

1280 = 720

x = 400

then cross multiply:

x720 = 512000

x = 711

so its:

711×400

to check:

1280/720 = 1.77

711×400 = 1.77

1.77 = 1.77

so your 400p resolution is 711×400

for example you got a source of 1280×720

then lets say you want to downsize to 480p

1280 = 720

x = 480

then cross multiply:

x720 = 614400

x = 853

so its:

853×480

to check:

1280/720 = 1.77

853/480 = 1.77

1.77 = 1.77

so your 480p resolution is 853×480

thats it you got it now