The exported captured movie is played back only in landscape mode and rotated

Question

Before posting a lot of code, here is the script:

• Using the code based on AVEditDemo from WWDC, I take the movie using the standard control in the portrait.
• I am posting a video using a code identical to the one in AVEditDemo, which uses Core Animation.

When I play the resulting video using the Camera application, it rotates 90 degrees and is no longer a “portrait” (now it’s in the landscape) and is crushed. (The aspect ratio seems to have been changed, width → height and height → width.

Spent many hours on it, and I'm at a loss.

The desired result is a film identical to the recorded original. (With animated overlay in the end).

To see this, just download and run Apple’s AVEditDemo, turn the “ON” heading on, and export the movie.

Answer 1

I think the short answer is this:

When processing the original video, you want to get "preferredTransform":

AVAssetTrack *sourceVideo = [[sourceAsset tracksWithMediaType:AVMediaTypeVideo]lastObject]; CGAffineTransform *preferredTransform = [sourceVideo preferredTransform]; 

and then when you write the final video, you will do something similar to this:

 AVMutableComposition *composition = [AVMutableComposition composition]; AVMutableCompositionTrack *compositionVideoTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid]; AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; [compositionVideoTrack setPreferredTransform:preferredTransform];