Rotate Landscape video

rotate_video.m

//setting up the first video based on previous recording
CMTimeRange videoDuration = CMTimeRangeMake(kCMTimeZero, [self.previousRecording duration]);
AVAssetTrack *clipVideoTrack = [[self.previousRecording tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
AVAssetTrack *clipAudioTrack = [[self.previousRecording tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
[compositionVideoTrack insertTimeRange:videoDuration ofTrack:clipVideoTrack atTime:nextClipStartTime error:nil];
[compositionAudioTrack insertTimeRange:videoDuration ofTrack:clipAudioTrack atTime:nextClipStartTime error:nil];

//our first track instruction - set up the instruction layer, then check the orientation of the track
//if the track is in landscape-left mode, it needs to be rotated 180 degrees (PI)
AVMutableVideoCompositionLayerInstruction *firstTrackInstruction =
     [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:clipVideoTrack];

if([self orientationForTrack:clipVideoTrack] == UIDeviceOrientationLandscapeLeft) {
    CGAffineTransform rotation = CGAffineTransformMakeRotation(M_PI);
    CGAffineTransform translateToCenter = CGAffineTransformMakeTranslation(640, 480);
    CGAffineTransform mixedTransform = CGAffineTransformConcat(rotation, translateToCenter);
    [firstTrackInstruction setTransform:mixedTransform atTime:kCMTimeZero];
}
    
    
 
 // Checking orientation for track .... 
    
- (UIInterfaceOrientation)orientationForTrack:(AVAsset *)asset
{
    AVAssetTrack *videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    CGSize size = [videoTrack naturalSize];
    CGAffineTransform txf = [videoTrack preferredTransform];
    
    if (size.width == txf.tx && size.height == txf.ty)
        return UIInterfaceOrientationLandscapeRight;
    else if (txf.tx == 0 && txf.ty == 0)
        return UIInterfaceOrientationLandscapeLeft;
    else if (txf.tx == 0 && txf.ty == size.width)
        return UIInterfaceOrientationPortraitUpsideDown;
    else
        return UIInterfaceOrientationPortrait;
}