user14463: 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 ?

user1871: 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.

14463: <p>I have an .mp4 format video filmed in portrait format, when currently played on any <code>landscape</code> format device the people appear sideways.</p>

<p>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.</p>

<p>Any suggestions ?</p>
 1871: <p>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 <a href="https://ffmpeg.org/download.html" rel="nofollow">ffmpeg</a>, a free command line tool.</p>

<pre><code>ffmpeg -i input.mp4 -c copy -metadata:s:v rotate=90 output.mp4
</code></pre>

<p>If your landscape devices don't understand or obey the rotation tag,</p>

<pre><code>ffmpeg -i input.mp4 -c copy -vf transpose=2 -c:v libx264 -crf 20 output.mp4
</code></pre>

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

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