On Mon, 3 Aug 2020 19:21:17 +0200 (GMT+02:00), Libor Striz wrote:

the easiest method is to rotate it directly in the video player.
nointermediate conversion needed.

While rotating it every time anyone views it will work,
each person has to figure out how to do that on each
platform that is viewing the video.

That's not efficient, IMHO, overall.

Additionally, if a video player does not have a particular desired
feature,
an Avisynth script can do near any video preprocessing,
limited only by CPU ( and eventually GPU ) performance.

Thanks for the suggestion of Avisynth, which I have, but I haven't used it
https://i.postimg.cc/Wz0vLjWj/editors.jpg

My log files contain this snippet, which includes avisynth:

o ShotCut freeware pretty much handles everything fantastically
https://www.shotcutapp.com/download/
o Handbrake freeware is cross platform compatible
https://handbrake.fr/
o Super freeware used to be the best (but get the older versions!)
http://www.videohelp.com/tools/SUPER/old-versions (no longer there)
o Others are VirtualDub, AviDemux, AviSynth, oxelon, totallyfreeconverter
https://sourceforge.net/projects/virtualdub/files/virtualdub-win/
https://sourceforge.net/projects/avidemux/files/latest/download
https://sourceforge.net/projects/avisynth2/files/latest/download
http://www.oxelon.com/media_converter.html
https://sourceforge.net/projects/oxelonmediaconv/files/oxelonmediaconv/oxelonplugins/oxelonplugins.exe/download
http://www.sabsoft.com/TotallyFreeConverter.htm

o And the US/Euro patents expired on ffmpeg so you no longer need lame
https://www.ffmpeg.org/legal.html
--
The experiences of others drastically reduces the high cost of freeware.