Guys. I use a Samsung Galaxy S5 for video (sometimes) and just recently I have had a display problem.

NOTE: No settings have been changed and they have been set identical to another S5 phone which works properly.
The Display - Screen Rotation is set to ON for both.

Normally, when you rotate the phone the image or videa displayed rotates and resizes to fit the new orientation.
On the crook phone, this no longer happens for video playback only. (It still works for photos.)

So now, if you change the orientation of the phone between vertical and horizontal, the playing video just stretches to the
edge of the screen. The images below illustrate the problem, showing two videos that were taken in each orientation.
Nothing wrong happens if you play the videos in the orientation they were recorded in.

My interim solution: Install and use the VLC Player app to play videos. It now displays videos properly. But the Samsung video
player is still installed and doesn't work properly anymore. So that eliminates a hardware problem.

So I'm wondering how to fix the Samsung player. Are there any hidden settings etc?

Here are illustrations of what I mean. In each case, the Samsung video player displays the loaded video correctly, but stretches
it when playing.

1. Video shot in portrait orientation and played in landscape orientation (should play as displayed)...
Vert-vid.jpg

2. Video shot in landscape orientation and played in portrait orientation (should play as displayed)...
hor-vid.jpg