I just grabbed a vertical video from my phone in mp4 format. VLC plays the video in vertical orientation.
Gifcurry loads and converts the video fine, but insists on rotating the video -90 degrees so that it shows as a horizontal video.
This is an issue because I have a neck hernia and can't tip my head sideways to view the resulting gif right side up.
Installed Gifcurry from the AUR (version 6.0.1.0)