[FFmpeg-user] Autorotation issues - portrait orientation screen

[Andrey Goreev]

Hello,

I have 1920x1080 videos with rotation flag 90. After I use this command:

ffmpeg -hide_banner -loglevel "${loglevel}" -y -i "${f}" -f mp4 -c:a "${ca}" -b:a "${ba}" -c:v "${cv}" -crf "${crf}" -preset "${preset}" -map_metadata 0 "${f%.*}_${suffix}.mp4"

where:

cv="libx264"
crf="23"
preset="slow"
ca="libfdk_aac"
ba="192k"
loglevel="warning"
suffix="${cv//lib/}"

the output is 1920x1080 without rotation (rotation 0).

Such output files look just fine on a desktop screen (landscape orientation) however they become too small to watch on a mobile screen (portrait orientation).
So what I want is:
Turn off the autorotation for files with rotation flag: 90 and instead flip their resolution e.g. 1920x1080 rotated 90 will become 1080x1920 rotated 0.
I am wondering if anyone could point me to a right direction on how to accomplish this. Any ideas would be greatly appreciated.
CheersAG