Video Display Playback Sideways or Upside Down
Video Sideways Playback
Often the reason your iPhone videos playback sideways on computer is because the phone was held vertically (the way you talk on the phone) during the recording of the video. If you hold your iPhone vertically, the video records in 9×16 aspect ratio and plays sideways on a computer or HDTV screen. Computers or HDTV screens required videos to be in 16×9 aspect ratio.
Video Upside Down Playback
Videos recorded in landscape mode appear upside down during playback if the home button was on the left-hand side during recording.
How to Correct
Using a third party software, you need to rotate the video. You should be able to do this in Quicktime if you have it or use a free software. Here is an example of a free software http://video-rotator.en.softonic.com/. Instant Customer does not endorse third party software. Please exercise Due diligence before downloading any software.