App to rotate .mp4 video for Windows or Android I have an .mp4 format video filmed in portrait format, when currently played on any landscape format device the people appear sideways.

I would like a sipmle app for either Windows™ or Android OS to only rotate the video so it plays 'portrait format' on any 'landscape format' device, such as a Smart TV.

Any suggestions ?
If I've understood you correctly, your video appears upright when viewed in portrait orientation and rotated in landscape. This suggests the image is stored in a landscape matrix but with no rotation tag set. If so, there are two things you can try using ffmpeg, a free command line tool.

ffmpeg -i input.mp4 -c copy -metadata:s:v rotate=90 output.mp4


If your landscape devices don't understand or obey the rotation tag,

ffmpeg -i input.mp4 -c copy -vf transpose=2 -c:v libx264 -crf 20 output.mp4


The 2nd command will re-encode the video portion of your file. CRF controls the quality - lower is better but will produce bigger files.

In the commands, you may have to switch the 90 with -90 and 2 with 1 depending on how the video was stored.