Yep sadly Im having same problem with my Iphone 5.
I will record a video in portrait mode, i then sync my iphone up on2 my pc windows 7, i open my iphone storage n can see the videos n photos i have saved in my camera roll. I drag my video into the correct video folder on my pc, i then add my file (new recorded video) in my itunes library n then click sync. Wen sync has finished i unplug my iphone and then open my videos file tab on my iphone n find my new video, i click play but my video is stuck sideways (landscape) even tho it was recorded in portrait mode. So i have heads missing n it will not rotate. I have contacted Apple on phone and went into the Apple shop 2day and they have no idea why its doing this and the guy at the genius bar said i cant help u sorry and he even asked other people for help.
Can anyone help with y my videos r stuck on portrait once i have moved them n synced them? If i dont move them out of camera roll they will rotate but once i move them n sync dats wen the prob happens.
I always did this with my iphone 3gs so not sure y now all the videos i sync which i recorded with my 3gs or my new iphone 5 r stuck on landscape mode even tho they r recorded in portrait. I used 2 b able 2 turn my mob around n da video would rotate either landscape or portrait.
Plz any help coz its very dissapointing and frustrating especially for me to have to drive one hour 2 my closest Apple store n they couldnt even help me.
I have had so many dramas with this Iphone 5....not happy