Sequence dimensions don't match Premiere Pro

[Swandive stream]

So here's the issue. I'm trying to create a video for YouTube at 1080p resolution. The After Effects sequence is 1920x1080px as is Premiere but for some reason in Premiere it is much wider, the result being when I embed the After Effects sequence I get vertical letterboxing. It seems to only affect certain sequences. Why is there a huge mismatch? Square pixels?

P.s. I'm aware the image here outputs weirdly, the video output isn't compressed this way

Ignoring the weird aspect ratio in this output, note the black bars

Sequence in After Effects

Sequence in Premiere

[Mylenium]

Yes, your pixel aspect ratio settings are wrong, in this case in Premiere. HD video is always square pixels, only some broadcast workflows and recording formats like XDCAM use non-square PAR, which is not relevant for YouTube however. Change your settings to enforce correct square-ishness all the way.

Mylenium

[RobShultz · Accepted solution]

Agreed. At the bottom of the comp window look for an icon with a double horizontal arrow and click that box. See if that helps.

And yes using videos with all square pixels or converting them to all square pixels will serve you well.